text:
|Publication number
|Publication type
|Application number
|Publication date
|Nov 22, 2011
|Filing date
|Sep 11, 2007
|Priority date
|Mar 9, 2007
|Fee status
|Also published as
|Publication number
|Rabih Chrabieh, Samir S. Soliman
|Original Assignee
|Qualcomm, Incorporated
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (60), Non-Patent Citations (17), Referenced by (3), Classifications (11), Legal Events (2)
|External Links: USPTO, USPTO Assignment, Espacenet
The present Application for Patent claims priority to Provisional Application No. 60/896,480, filed Mar. 22, 2007, entitled, QUADRATURE IMBALANCE MITIGATION USING UNBIASED TRAINING SIGNALS, status Pending.
The present Application for Patent is a continuation-in-part of Patent Application No. U.S. Ser. No. 11/684,566, filed Mar. 9, 2007, entitled, QUADRATURE MODULATION ROTATING TRAINING SEQUENCE, status pending; assigned to the assignee hereof and hereby expressly incorporated by reference herein.
The present Application for Patent is a continuation-in-part of Patent Application No. and U.S. Ser. No. 11/755,719, filed May 30, 2007, entitled, QUADRATURE IMBALANCE MITIGATION USING UNBIASED TRAINING SEQUENCES, status pending, assigned to the assignee hereof and hereby expressly incorporated by reference herein.
The present Application for Patent is related to U.S. Patent Application entitled, CHANNEL ESTIMATION USING FREQUENCY SMOOTHING, filed concurrently herewith, and assigned to the assignee, which is hereby incorporated by reference in its entirety.
1. Field
This invention relates generally to communication channel estimation and, more particularly, to systems and methods for improving the use of quadrature modulation unbiased training sequences in the training of receiver channel estimates, by removing quadrature imbalance errors.
2. Background
There are a number of errors that can be introduced into the receiver that detrimentally affect channel estimations and the recovery of the intended signal. Errors can be introduced from the mixers, filters, and passive components, such as capacitors. The errors are exacerbated if they cause imbalance between the I and Q paths. In an effort to estimate the channel and, thus, zero-out some of these errors, communication systems may use a message format that includes a training sequence, which may be a repeated or predetermined data symbol. Using an Orthogonal Frequency Division Multiplexing (OFDM) system for example, the same IQ constellation point may be transmitted repeatedly for each subcarrier.
In an effort to save power in portable battery-operated devices, some OFDM systems use only a single modulation symbol for training. For example, a unique direction in the constellation (e.g., the I path) is stimulated, while the other direction (e.g., the Q path) is not. The same type of unidirectional training may also be used with pilot tones. Note: scrambling a single modulation channel (e.g., the I channel) with �1 symbol values does not rotate the constellation point, and provides no stimulation for the quadrature channel.
In the presence of quadrature path imbalance, which is prevalent in large bandwidth systems, the above-mentioned power-saving training sequence results in a biased channel estimate. A biased channel estimate may align the IQ constellation well in one direction (i.e., the I path), but provide quadrature imbalance in the orthogonal direction. It is preferable that any imbalance be equally distributed among the two channels.
Assuming the errors are small:
The first component on the right hand side, cos(ωt), is the ideal I path slightly scaled. The second component, −2Δφ.sin(ωt), is a small leakage from the Q path. After down-conversion of the impinging waveform:
The errors result in the misinterpretation of symbol positions in the quadrature modulation constellation, which in turn, results in incorrectly demodulated data.
Wireless communication receivers are prone to errors caused by a lack of tolerance in the hardware components associated with mixers, amplifiers, and filters. In quadrature demodulators, these errors can also lead to imbalance between the I and Q paths, resulting in improperly processed data.
A training signal can be used to calibrate receiver channels. However, a training signal that does not stimulate both the I and Q paths, does not address the issue of imbalance between the two paths. An unbiased training sequence can be used to stimulate both the I and Q paths, which results in a better channel estimate. Conventionally, channel estimates are derived from predetermined information associated with the positive (+f) subcarriers. Even better channel estimates can be obtained if the negative (−f) subcarriers are used to derive an estimate of any residual quadrature imbalance.
Accordingly, a method is provided for removing quadrature imbalance errors in received data. The method accepts an unbiased training sequence in a quadrature demodulation receiver. An unbiased training sequence has a uniform accumulated power evenly distributed in a complex plane, and includes predetermined reference signals (p) at frequency +f and predetermined mirror signals (pm) at frequency −f. The unbiased training sequence is processed, generating a sequence of processed symbols (y) at frequency +f, representing complex plane information in the unbiased training sequence. Each processed symbol (y) is multiplied by the mirror signal (pm), and an unbiased quadrature imbalance estimate Bm is obtained at frequency (−f).
For example, the unbiased training sequence may be accepted on a first subcarrier, and the quadrature imbalance estimate obtained for the first subcarrier. Then, the method accepts quadrature modulated communication data on the first subcarrier in symbol periods subsequent to accepting the unbiased training sequence. A processed symbol (yc) is generated for each communication data symbol, and each processed symbol (yc) is multiplied by a quadrature imbalance estimate to derive an imbalance-corrected symbol.
The method also multiplies the processed symbol (y) by a conjugate of the reference signal (p*) to obtain an unbiased channel estimate (hu) at frequency +f. Using the quadrature imbalance and channel estimates, imbalance-corrected symbols can be derived.
Additional details of the above-described method, and a system for removing quadrature imbalance errors in received data are presented below.
Various embodiments are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing these embodiments.
As used in this application, the terms "processor", "processing device", "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, generation, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal).
Various embodiments will be presented in terms of systems that may include a number of components, modules, and the like. It is to be understood and appreciated that the various systems may include additional components, modules, etc. and/or may not include all of the components, modules etc. discussed in connection with the figures. A combination of these approaches may also be used.
The various illustrative logical blocks, modules, and circuits that have been described may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The methods or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in the node, or elsewhere. In the alternative, the processor and the storage medium may reside as discrete components in the node, or elsewhere in an access network.
The transmitter 402 may include a transmitter subsystem 407, such as a radio frequency (RF) transmitter subsystem that uses an antenna 408 to communicate via an air or vacuum media. However, it should be understood that the invention is applicable to any communication medium (e.g., wireless, wired, optical) capable of carrying quadrature modulated information. The transmitter subsystem 407 includes an in-phase (I) modulation path 410, or a means for generating I modulation training information in the time domain having an accumulated power. The transmitter subsystem 407 also includes a quadrature (Q) modulation path 412, or a means for generating Q modulation training information in the time domain having an accumulated power equal to the I modulation path power. I path information on line 404 a is upconverted at mixer 414 with carrier fc, while Q path information on line 404 b is upconverted at mixer 416 with a phase shifted version of the carrier (fc+90�). The I path 410 and Q path 412 are summed at combiner 418 and supplied on line 420. In some aspects, the signal is amplified at amplifier 422 and supplied to antenna 408 on line 406, where the unbiased training sequences are radiated. The I and Q paths may alternately be referred to as I and Q channels. A unbiased training sequence may also be referred to as a rotating training signal, a quadrature balanced training sequence, balanced training sequence, balanced training sequence, or unbiased training signal.
For example, the unbiased training sequence may be initially sent via the I modulation path 410, with training information subsequently sent via the Q modulation path 412. That is, the training signal may include information, such as a symbol or a repeated series of symbols sent only via the I modulation path, followed by the transmission of a symbol or repeated series of symbols sent only via the Q modulation path. Alternately, training information may be sent initially via the Q modulation path, and subsequently via the I modulation path. In the case of single symbols being sent alternately through the I and Q paths, the transmitter sends a rotating training signal. For example, the first symbol may always be (1,0), the second symbol may always be (0,1), the third symbol (−1,0), and the fourth symbol (0,−1).
However, it is not necessary to simply alternate the transmission of symbols through the I and Q modulations paths to obtain symbol rotation, as described above. For example, the transmitter may send training information simultaneously through both the I and Q modulation paths, and combine I and Q modulated signals.
The above-mentioned rotating type of unbiased training sequence, which initially sends training signal via (just) the I modulation path, may be accomplished by energizing the I modulation path, but not energizing the Q modulation path. Then, the transmitter sends a training signal via the Q modulation path by energizing the Q modulation path, subsequent to sending training information via the I modulation path. The training symbols can also be rotated by supplying symbols, each with both I and Q components, as is conventionally associated with quadrature modulation.
Typically, the transmitter 402 also sends quadrature modulated (non-predetermined) communication data. The unbiased training sequence is used by a receiver (not shown) to create unbiased channel estimates, which permit the non-predetermined communication data to be recovered more accurately. In one aspect, the quadrature modulated communication data is sent subsequent to sending the unbiased training sequence. In another aspect, the unbiased training sequence is sent concurrently with the communication data in the form of pilot signals. The system is not limited to any particular temporal relationship between the training signal and the quadrature modulated communication data.
To be unbiased, the symbol values associated with any particular subcarrier may periodically vary. The simplest means of evenly distributing information in the complex plane when there are an even number of symbols per message, is to rotate the symbol value 90 degrees every period. As used herein, a message is a grouping of symbols in a predetermined format. A message has a duration of several symbols periods. One or more symbols may be transmitted every symbol period. Some messages include a preamble preceding the main body of the message. For example, a message may be formed as a long packet containing many OFDM symbols. Each OFDM symbol contains many subcarriers. In some aspects, the message preamble includes the unbiased training sequence. In other aspects, the unbiased training sequence is a sequence of pilot signals that are transmitted simultaneously with the non-predetermined communication data.
If an uneven number of symbols are used in the training sequence of a message, a methodology that rotates the phase of the symbol by 90 degrees every period is not always useful. For a sequence of 3 symbols, a 60-degree or 120-degree rotation may be used to evenly distribute the symbol values in the complex plane. For 5 symbols, a 180/5-degree or 360/5-degree rotation may be used. If the number of symbols in a training sequence is a prime number, combination solutions can be used. For example, if there are a total of 7 symbols in a message, then a rotation of 90 degrees may be used for the first 4 symbols, and a rotation of 120 (or 60) degrees for the next three symbols. In another aspect, the unbiased training sequence may be averaged over more than one message. For example, if a message includes 3 training symbols, then the combination of 2 messages includes 6 symbols. In the context of a 6-symbol training signal, a rotation of 90 degrees may be used between symbols.
Since power is a measurement responsive to the squaring of a complex symbol value, the power associated with a symbol vector at angle θ in complex space may also be considered to be the power at (θ+180). Hence, the accumulated power at an angle of 60 degrees is the same as the power at 240 degrees. Alternately stated, the power associated with a symbol at angle θ may be summed with the power at angle (θ+180). By summing the power at angles θ and (θ+180), complex space, as considered from the perspective of power, only spans 180 degrees. For this reason, a uniform accumulation of power is evenly distributed in complex space when the unbiased training sequence consists of only 2 orthogonal symbols, or 3 symbols separated by 60 degrees.
Likewise, when the transmitter generates i occurrences of the reference signal and mirror signal, the signal pair values p and pm may, but need not, vary for every occurrence. For example, the transmitter may nullify the sum of the products (pi�pim) by generating information as a complex value that remains constant for every occurrence, to represent p. To represent pm, the transmitter may generate information as a complex value that rotates 180 degrees every occurrence. However, there are almost an infinite number of other ways that the products (pi�pim) may be nulled.
In another aspect, the transmitter generates i occurrences of reference signal (p) and mirror signal (pm), and a product (pi�pim) for each occurrence. The transmitter pairs occurrences and nullifies the sum of the products from each paired occurrence.
For example, one or more messages may contain a temporal sequence of N pilot tones, for a given subcarrier f, with N pilot tones for the mirror subcarrier −f. As noted above in the discussion of
As described above, simple examples of creating an unbiased training sequence include either the rotation of symbols by 90 degrees in the time domain, or in the frequency domain, maintaining the symbol reference on +f, but flipping the sign the mirror on −f. Both these examples used 2 pair of tones and satisfy the equation p1�p1m+p2�p2m=0.
Alternately expressed, the unbiased training sequence may include:
The unbiased training sequence can be obtained by averaging. The principle of unbiased training sequence dictates that the pilot must satisfy:
p 1 �p 1m +p 2 �p 2m +p 3 �p 3m +p 4 �p 4m=0.
As a variation, the unbiased training sequence can be organized as follows:
p 1 �p 1m +p 2 �p 2m=0 and p 3 �p 3m +p 4 �p 4m=0.
As used herein, the above-mentioned "uniform accumulation of power" may be exactly equal accumulations in each complex plane direction, as in many circumstances it is possible to transmit and receive an unbiased training sequence with an error of zero. That is, the training sequence is 100% biased. Alternately stated, the sum of pi�pim=0, as described above. In a worst case analysis, L pilot symbols are averaged, each having a uniform accumulated power as follows:
|sump i �p im|−sum|pi| 2 =L.
If L is 100%, and if a |sum pi�pim|=L/4, then the (uniform accumulated power) error is 25%. An unbiased training sequence with a 25% error still yields excellent results. If L/2 is used (a 50% error), good results are obtained as the IQ interference from the channel estimate still decreases by 6 dB.
For example, an Ultra Wideband (UWB) system uses 6 symbols transmitted prior to the transmission of communication data or a beacon signal. Therefore, 3 consecutive symbols may be generated on the I modulation path followed by 3 consecutive on the Q modulation path. Using this process, the Q channel need only be activated briefly, for 3 symbols, before returning to sleep. However, there are many other combinations of symbols that may be used to generate an unbiased training sequence.
Viewing either
sum a i(k)�a i(k)=0;
where k is a number of samples per symbol period. Note: the "dot" between the ai and ai symbols is intended to represent a conventional multiplication operation between scalar numbers.
Since the symbol ai is typically a subcarrier with a periodic waveform, there is no one particular value for a. That is, ai varies with time, and could be represented as ai(t). However, if t samples are obtained, the symbol may be expressed as ai(kT), or ai(k), assuming T is normalized to 1. For time domain systems, the summation over k disappears. With only one sample per symbol, the symbol and sample become the same and the equation can be written as:
sum a i �a i=0.
To illustrate with a simple 2-symbol orthogonal unbiased training sequence, if the first symbol (i=1) has an angle of 0 degree, an equal amount of power must exist at an angle of 180 degrees in order to satisfy the equation. Likewise, if the second symbol is at 90 degrees, and equal amount of power must exist at an angle of 270 degrees. Other more complication examples may require that the symbols be summed over the index of i to obtain the nulled final result.
Alternately considered, the formula sum ai�ai=0 refers to the fact that if a projection is made in any direction in the complex plane and the power calculated, the power is always the same, regardless of the angle. The power in direction φ is:
sum|Re a i (−jφ)|2=0.5 sum|a i|2+0.5 Re (−2jφ)sum a
This power is constant for all φ if and only if sum ai�ai=0.
It can be shown that the frequency domain formula (sum pi�pim=0) is equivalent to sum ai�ai=0. The time domain signal corresponding to pi and pim is:
a i =p i exp(j2πft)+p im exp(−j2πft);
since pi modulates +f and pim modulates −f.
Within one symbol i, the integral over time of ai�ai is:
integral a i �a i=integral {pi�pi exp(j4πft)+pim �p im exp(−j4πft)+p i �p im }=p i �p im;
since the exp(j4πft) rotates several times and vanishes when integrated in one symbol.
So ai�ai cumulated in one symbol is equal to pi�pim.
If all the symbols are added up:
sum integral a i �a i=sum p i �p im=0.
The receiver 902 has an in-phase (I) demodulation path 906 for accepting I demodulation training information in the time domain having an accumulated power. A quadrature (Q) demodulation path 908 accepts Q demodulation training information in the time domain. When considering the unbiased training sequence, the Q path has an accumulated power equal to the I modulation path power. As is conventional, the receiver 902 includes analog-to to digital converters (ADC) 909, a fast Fourier transformer (FFT) 910, a deinterleaver 912, and a decoder 914.
The quadrature demodulation receiver 902 accepts an unbiased training sequence of predetermined reference signals (p) at frequency (+f) and predetermined mirror signals (pm) at frequency (−f) with a uniform accumulated power evenly distributed in a complex plane. The receiver 902 generates a sequence of processed symbols (y) at frequency (+f) representing complex plane information in the unbiased training sequence, multiplies each processed symbols (y) by the mirror signal (pm), and supplies a quadrature imbalance estimate (Bm) at frequency (−f). For simplicity, it is shown that the generation of the processed symbols and the multiplication by the mirror symbols is performed in symbol generator 916.
As noted above in the discussion of the transmitter, the unbiased training sequence is a temporal sequence of complex plane symbols with equal accumulated power in a plurality of directions. Alternately considered, the receiver accepts the unbiased training sequence as a signal pair including a complex value reference signal (p) at frequency +f and a complex value mirror signal (pm) at frequency −f, where the product (p�pm) is null. For example, the receiver accepts the unbiased training sequence as i occurrences of the reference signal (p) and the mirror signal (pm), where the sum of the products (pi�pim) is null.
In some aspects, the receiver 902 accepts an unbiased training sequence with a plurality of simultaneously accepted predetermined reference signals (pn) and a plurality of simultaneously accepted predetermined mirror signals (pnm). For example, n pilot symbols may be accepted every symbol period. The receiver 902 generates a plurality of processed symbols (yn) from the corresponding plurality of reference signals, multiplies each processed symbol by its corresponding mirror signal, and obtains a plurality of channel estimates (Bnm) from the corresponding plurality of (yn)(pnm) products.
More explicitly (see
In another aspect, the receiver accepts an unbiased training sequence with temporal sequence of n predetermined reference signals (pn) and n predetermined mirror signals (pnm), see
More explicitly as shown in
Returning to
The receiver calculates an imbalance-corrected symbol (z)=y−(Bm/hm*)ym*, if the signal-to-noise ratio (SNR) of (xm) is greater than j, and otherwise sets (z) equal to (y). For simplicity, zero-forcing (ZF) calculator 918 is shown supplying the imbalance-corrected symbols in response to receiving processed symbols, channel estimates, and quadrature imbalance estimates. The receiver (i.e., ZF calculator 918) calculates (zm)=ym−(B/h*)y*, if the SNR of (x) is greater than j, and otherwise, sets (zm) equal to (ym). The receiver uses (z) and (zm) in the calculation of (x) and (xm), respectively, which is outside the scope of this disclosure. In one aspect, as explained in greater detail below, the receiver calculates (zm) and (z) using the quadrature imbalance estimates (B) and (Bm), respectively, if the SNR is greater than 1 (j=1).
Although not specifically shown, the receiver of
Training sequences, whether enabled in a preamble or as pilot signals are similar in that the information content of transmitted data is typically predetermined or "known" data that permits the receiver to calibrate and make channel measurements. When receiving communication (non-predetermined) data, there are 3 unknowns: the data itself, the channel, and noise. The receiver is unable to calibrate for noise, since noise changes randomly. Channel is a measurement commonly associated with delay and multipath. For relatively short periods of time, the errors resulting from multipath can be measured if predetermined data is used, such as training or pilot signals. Once the channel is known, this measurement can be used to remove errors in received communication (non-predetermined) data. Therefore, some systems supply a training signal to measure a channel before data decoding begins.
However, the channel can change, for example, as either the transmitter or receiver moves in space, or the clocks drift. Hence, many systems continue to send more "known" data along with the "unknown" data in order to track the slow changes in the channel.
Although not specifically shown, the transmitter of
Modern high data rate communication systems transmit signals on two distinct channels, the in-phase and quadrature-phase channels (I and Q). The two channels form a 2D constellation in a complex plane. QPSK and QAM are examples of constellations. The I and Q channels may be carried by RF hardware that cannot be perfectly balanced due to variations in RF components, which results in IQ imbalance. In the increasingly common direct conversion systems, the imbalance issued are even greater. IQ imbalance distorts the constellation and results in crosstalk between the I and Q channels: the signal interferes with itself. Increasing transmission power does not help, since self-generated interference increases with the signal power. The signal-to-noise ratio (SINR) reaches an upper bound that puts a limit on the highest data rate attainable with a given RF hardware. In order to increase the data rate, a costly solution is to use fancier, more expensive hardware. A possibly less costly solution is to digitally estimate IQ imbalance and compensate for it. The concepts of digital estimation and compensation algorithms have been previously advanced in the art. However, the solutions tend to be expensive because they do not rely on a special type of training sequence. These solutions often only consider imbalance at one side, usually at the receiver.
Examples are given below that focus on Orthogonal Frequency Division Multiplexing (OFDM), with insights for time domain systems, which study end-to-end imbalance, from transmitter to receiver. Moreover, in OFDM the imbalance is modeled as a function of frequency, taking into account variations in the frequency response of the filters.
Two kinds of enhancements are presented: one with zero cost that eliminates the interference from the channel estimate by using an unbiased training sequence. Substantial gains are achieved because the error of the channel estimate is often more detrimental to performance than the error in the data itself. A second, relatively low cost, enhancement compensates for data distortion, if more gain is needed.
A model of the IQ imbalance is provided below. Analysis is provided to show how conventional channel estimation using unbiased training sequences can mitigate part of the IQ imbalance. Then, a straightforward extension is provided to calculate the IQ imbalance parameters, proving that the algorithms are effective. Using the estimated parameters, a simple compensation algorithm is presented to mitigate data distortion. Simulation results for WiMedia's UWB are also given, as well as suggestions to amend the standard.
IQ Imbalance Model
IQ imbalance arises when the power (amplitude) balance or the orthogonality (phase) between the in-phase (I) and quadrature-phase (Q) channels is not maintained. IQ imbalance is therefore characterized by an amplitude imbalance 2ε and a phase imbalance 2Δφ.
Time Domain Signals
A complex symbol x is transmitted and received via the I and Q channels. In an ideal noiseless channel, the symbol x is received intact. But in the presence of IQ imbalance, a noisy or distorted version is likely received.
y=αx+βx*, (1)
α=cos(Δφ)+jε sin(Δφ),
β=ε cos(Δφ)−j sin(Δφ) (2)
are complex quantities modeling the imbalance, α≈1 and β≈0. Nonlinear model (1) is linearized via the vector form
B is the imbalance matrix. The second row is obsolete since it is a duplicate version of the first row. But it gives a same size and type input and output so imbalance blocks at transmitter and receiver can be concatenated, as described below. The imbalance matrix at the transmitter is defined by Bt, and at the receiver it is defined by Br.
One-Tap Channel
A one-tap channel is considered, suitable for OFDM. A one-tap channel h in appropriate matrix form is
With imbalance at transmitter and receiver, and in average while Gaussian (AWGN) noise n, vector form N=(n n*)T, the received signal is expressed as a concatenation of linear blocks
The overall result is that IQ imbalance and channel combine to create a global channel h′, plus an undesired distortion or interference characterized by a global imbalance parameter β′. The global imbalance parameter β′ changes when the channel changes, and may need to be estimated regularly.
Next, the condition is considered where the symbol x, rather than spanning the entire complex plane, is restricted to a given (1D) axis. For example, the axis may be associated with BPSK modulation, the real axis, the imaginary axis, or any axis in between. In this case, x*=kx may be written, where k is a complex constant (a rotation), and
If x is restricted to a unique axis, IQ imbalance vanishes, becoming an integral part of an overall channel response.
Frequency Domain Signals
While the previous model applies to time domain signals, a modification is now considered where the signal of interest x is given in frequency domain, at frequency f. In time domain, this signal is carried by a complex tone, xej2πft. Replacing terms in equation (1), the following is obtained
αxe j2πft +βx*e −j2πft. (7)
In OFDM, the interference created by IQ imbalance does not show up at the same frequency f, but rather at the mirror frequency −f, and vice versa. What is transmitted at −f creates interference on frequency +f. If signal xm is the signal transmitted at frequency −f, where index m denotes a quantity at mirror frequency −f, then at frequency −f the following is obtained
αm x m e −j2πft+βm x m *e j2πft. (8)
A generalization of the time domain equations has been used. The IQ imbalance parameters α and β are here a function of frequency. This models an imbalance due to different low-pass (base-band) or band-pass (IF) filters in the system. The I and Q paths cannot have the exact same filters and, hence, the imbalance varies with frequency. In time domain systems, this kind of imbalance exists but it is very expensive to compensate. An equalizer and an extension of the model to deal with different convolutions on different channels are required. So in the time domain, bulk or average imbalance is used. Frequency domain systems are able to take advantage of the plain equalizer structure and model the imbalance on a per frequency basis.
If the output of equations (7) and (8) are combined per subcarrier, the following is observed
Y=(αx+β m x m*)e j2πft
y m=(αm x m +βx*)e −j2πft. (9)
Omitting the subcarriers (automatically handled by the FFT), a linear model function of signals at +f and −f can be written as
In the frequency domain model, the second row is no longer obsolete. The model deals, in one shot, with a pair of mirror frequencies. A one-tap channel h at frequency f, and hm at frequency −f is modeled by the matrix
AWGN noise n at frequency f, and nm at frequency −f form the noise vector N=(n nm*)T. The end to end model is
h′, hm′ are the global channel taps, and β′, βm′ are the global imbalance parameters. The imbalance parameters change when the channels change and may need to be estimated regularly.
Since IQ imbalance generates interference exclusively from the mirror frequency, two interesting cases are noteworthy. If at the mirror frequency no signal is transmitted, or the channel is in a fade, no interference is created. If on the other hand, the signal or channel is strong, the interference can be strong. Hence, in OFDM, the effect of IQ imbalance is more problematic.
Conventional Channel Estimation
Before examining the compensation algorithms, it is shown how half of the problem can be solved at no cost, simply by using an unbiased training sequence. An unbiased training sequence fully eliminates the interference from the channel estimate, noticeably improving performance. In fact, the error in the channel estimate is often more detrimental than the error in the data, because the channel estimate tends to create a bias in the constellation.
The model (12) is stimulated with pilot tones. At frequency +f, the pilot p is transmitted, and at frequency −f, the pilot pm. Assuming, without loss of generality, that the pilots have a unit norm (the channel carries the effective power), the conventional channel estimate at frequency f is obtained by de-rotating by p*
By averaging several channel observations, the noise is automatically reduced (for clarity, noise de-rotation is omitted). With regard to the term β′mpm*p*, many OFDM systems (e.g., WiMedia's UWB) use a training sequence that is simply a repeated symbol. Therefore, this term does not decay with averaging. Applying a scrambling of +1 or −1 to the entire OFDM symbol does not help, as nothing changes when the sign of both p* and pm* are inverted. Rather, the following is accomplished: after cumulating a number of observations, the sum of the products is nullified
Σipipim=0. (14)
Often the training sequence consists of an even number of symbols, and it is enough to ensure each pair adds up to zero
p 1 p 1m +p 2 p 2m=0. (15)
Examples of unbiased training sequences
P2 = jp1
Second training symbol is a 90 degrees rotation of
first training symbol.
P2 = p1, p2m = −p1m
For positive frequencies maintain fixed pilot, for
negative frequencies constantly invert the sign.
Examples of simple sequences that satisfy the condition are given in Table 1. These types of training sequences are denoted as unbiased training sequences because, on one hand, unbiased channel estimates are produced, and on the other, the training signals equally spans the I and Q dimensions of the complex plane in time domain. For example, an unbiased training sequence is not concentrated along just the real axis.
As a proof: consider the unit norm complex scalar ai=piejθ=pime−jθ, half way between pi and pim. In time domain, the pilots add up to 2ai cos(2πft+θ). In time domain and in a given OFDM symbol, the 2 mirror pilots span a unique direction determined by the complex constant ai. If L symbols are transmitted, the total (or average, or cumulated) power in a direction φ is Σi|
IQ Imbalance Estimation
After estimating the global channel h′, the estimation of the global imbalance parameter βm′ is considered. Careful analysis of equation (12) reveals that this parameter can be obtained in manner very similar way to the conventional channel estimation. That is, βm′ can be treated like a "channel" carrying the pilot pm*. Hence, by de-rotating by pm, an estimate of the imbalance may be obtained. The condition for unbiased estimation of the imbalance is identical to equation (14).
In summary, using unbiased training sequences and two conventional channel estimations, good estimates of the end-to-end channel and imbalance parameter are obtained (Table 2).
TABLE 2 Estimation algorithm H′ β′m Derotate by p* Derotate by pm
Smoothing Over Adjacent Subcarriers
In addition to averaging over adjacent OFDM symbols, the channel estimate may be smoothed over adjacent subcarriers within one symbol. In OFDM, the cyclic prefix is designed to be short, and the channel is supposed to vary slowly from tone to tone. Likewise, the filters in the RF chain should have short temporal response and their frequency response also varies slowly, i.e., the IQ imbalance varies slowly across subcarriers. The same channel smoothing techniques can be used to smooth and improve the imbalance parameter estimate. By using unbiased training sequences, there is no interaction between the channel estimate and the imbalance estimate. Each estimated can be independently smoothed.
If a unique OFDM symbol is used for estimation, it is impossible to find an unbiased training sequence that satisfies equation (14). In this case, a nearly unbiased training sequence can be obtained by applying the summation from equation (14) over groups of 2 or more adjacent subcarriers. Then smoothing automatically cancels all or part of the interference from mirror frequencies. One solution is to rotate the pilot by 90 degrees on the adjacent subcarrier (moving in mirror directions on the positive and negative frequencies).
The use of unbiased training sequences and the above-mentioned conventional channel estimation results is a Least Squares (LS) estimator. Of all the LS estimators, the Minimum Mean Squared Error (MMSE) sense shows significant value.
Least Squares Estimator
L transmissions Xi, L noise terms Ni and L observations Yi, may be respectively concatenated into the 2 by L matrices
χ=(X 1 X 2 . . . X L)
y=(Y 1 Y 2 . . . Y L) (16)
Then, equation (12) becomes
y =H′+N. (17)
The unknown is H′. The LS estimator is
Ĥ′=yχ H(χχH)−1. (18)
When condition (14) is satisfied, it is easy to verify that χχH is diagonal (the cross terms vanish). It is proportional to an identity matrix since the pilots are normalized to unit norm. Then
Ĥ′=yχ H /L=1/LΣ i Y i X i H (19)
is precisely four conventional channel estimations with de-rotations respectively by pi*, pim, pim* and pi as described in the previous section. Two estimations are obtained for frequency f, and two estimations for mirror frequency −f.
Optimal Estimator
Unbiased training sequences and conventional channel estimations are an LS estimator. But any estimator Ĥ′=y χH(χχH)−1 is also an LS estimator. Below, it is shown that the use of unbiased training sequences results in an excellent estimator. Model (17) can be viewed as unknown information H′ sent via 2 consecutive transmissions over 2 vectors (rows of χ) in an L dimension space. We denote by χj, Nj and yj respectively row j of χ, N and y, where j∈{1,2}. Models (12) and (17) can be written
y 1 =h′χ 1+β′mχ2 +N 1
y 2=β′χ1 +h′ m χ 2 +N 2. (20)
There are 2 transmissions, each involving the 2 vectors χ1, χ2, and where each vector is carrying complex amplitude information to be estimated. The LS estimator consists of projecting onto each vector, in a parallel way to the other vector in order to cancel interference. A very good result is obtained when the 2 vectors are orthogonal, i.e., when dot product (14) is zero. Unbiased training sequences are by definition, training sequences that verify this condition. Other sequences use non-orthogonal vectors and suffer a loss of performance function of the angle between the vectors χ1 and χ2. Many OFDM systems currently use a very poor kind of training sequences where χ1, χ2 are collinear, and it is impossible to properly estimate the 4 entries in H′. These training sequences tend to estimate noisier versions of the channels h′ and h′m.
To calculate the Mean Squared Errors (MSE), the estimation error is Ĥ′−H′=NχH(χχH)−1. This is a 2 by 2 matrix, i.e., 4 error values. Each value can be isolated by multiplying left and right with combinations of the vectors (1 0)T and (0 1)T. Assuming ENNH is an identity matrix, or more generally a diagonal matrix with elements σ2 and σm 2, it can be shown that the MSE of ĥ′ and βm′ are, respectively, the first and second diagonal elements of σ2(χχH)−1. And for βm′ and ĥm′, the MSE are, respectively, the first and second diagonal element of σm 2(χχH)−1.
The total MSE is 2(σ2+σm 2)tr(χχH)−1. Now the problem is to find χ that minimizes tr(χχH)−1 subject to the constraint that total pilot power is constant, i.e., tr(χχH)=2L. Using an Eigen decomposition, the problem can be written as minimize Σ1/λj subject to Σλj is constant. The problem is solved with the Lagrange multipliers, and is typically optimum when all Eigen values are equal. This means χχH=LI is proportional to an identity matrix.
The total MSE has been minimized, and the resulting MSE per element is either σ2/L or σm 2/L. But this MSE per element is likely to be the best that can be obtained, even if a unique vector transmission is used. The MSE is unlikely to be improved for a 2 vector transmissions, and therefore the MSE per element has been minimized. The unbiased training sequences plus conventional channel estimator are the MMSE of all LS estimators.
IQ Imbalance Compensation
If the gain from the unbiased channel estimate is not enough, the IQ imbalance parameters may be estimated (as described previously) and applied to compensate for data distortion. H′ is estimated in model (12), Y=H′X+N. Now the focus turns to the unknown data X. The model is the same as any 2-tap channel with cross-correlations. Any channel equalization algorithm can be fitted. A simple equalization algorithm is presented suitable for the ubiquitous bit-interleaved coded QAM and fading channels.
One concern with the Zero-Forcing (ZF) approach H′−1Y=X+H′−1N is that it enhances noise when the mirror channel is weak, unless an accounting is made for the complicated colored noise. The present solution uses ZF, but only when the mirror channel is not weak. In equation (12), replacing xm by its value, the following is obtained
is noise enhancement. Note: it is assumed the second order imbalance term β′*βm′<<h′hm′*. When this approximation is invalid, the corrected channel
is considered, which entails precise estimation of the channel and imbalance parameters.
Basically, the ZF technique consists of computing
z=y−(βm ′/h m′*)y m *≈h′x+n′+n. (22)
By subtracting the mirror frequency quantity (βm′/hm′)ym from the received signal y, the simple channel model with no IQ imbalance is obtained. The rest of the decoding chain is unchanged.
This solution works well as long as the noise enhancement is weaker than the original interference from IQ imbalance, i.e., |n′|2<|βm′xm*|2. If not, then the original y is used rather than the imbalance corrected z. It is unnecessary to estimate n′ in order to make a decision. A robust average-wise improvement may be elected. So, considering the expected values
When the mirror frequency's signal to noise ratio SNRm is greater than 1, the imbalance corrected term z is used. Otherwise, the original signal y is kept. Due to channel and imbalance estimation imprecision, it is safer to use a larger SNR, for example, SNRm>2 works well for WiMedia UWB. Note that SNRm can usually be obtained from the global SNR via the formula SNRm=|hm′|2SNR.
Table 3 summarizes the ZF algorithm with noise enhancement avoidance.
TABLE 3 Compensation algorithm SNRm < 1 + δ SNRm > 1 + δ z = y z = y − (βm ′/hm ′)ym
Simulation Results
WiMedia UWB: loss from IQ imbalance at PER of 10−2
Current Standard
Unbiased Training
3.1 dB
1.1 dB
0.35 dB
End-to-end IQ imbalance and channel combine to form a global 2 by 2 channel matrix. The use of unbiased training sequences achieves considerable gains at no cost. The unbiased training sequences automatically cancel end-to-end self-generated interference from the channel estimate. Moreover, such training sequences are ideal for estimating IQ imbalance parameters, and a simple algorithm is given to compensate for data distortion: Zero-Forcing with noise enhancement avoidance.
WiMedia UWB, in particular, benefits from the following enhancement: the conventional biased training sequence that consists of 6 symbols exclusively transmitted on the I channel can be divided in 2 halves to create an unbiased sequence. The first 3 symbols are sent on the I channel, and the last 3 symbols are sent on the Q channel. By uniformly spanning the complex plane, an unbiased training sequence is created with large gains for high data rates. For backward compatibility, this scheme may be reserved for high data rate modes and signaled via the beacons, or the training sequence type may be blindly detected.
In OFDMA (e.g., WiMAX), the subcarriers f and −f can be assigned to different users. Considerable interference can arise if power control drives one user to high power level. It is therefore a good idea to locate the pilots of different users on mirror subcarriers. The pilots should satisfy the unbiased training sequence criterion. Each user automatically benefits without any extra effort. The pilots may hop to different locations while maintaining mirror positions.
The time domain formulas can be extended to Code Division Multiple Access (CDMA) with a Rake equalizer combining several one-tap channels. Unbiased training sequences automatically improve the channel estimate per tap. A simple unbiased training sequence for CDMA consists of constantly rotating the complex symbols by 90 degrees.
Step 1102 accepts an unbiased training sequence in a quadrature demodulation receiver. The unbiased training sequence has a uniform accumulated power evenly distributed in a complex plane, and includes predetermined reference signals (p) at frequency +f and predetermined mirror signals (pm) at frequency −f. As explained in detail above, the unbiased training sequence is a temporal sequence of complex plane symbols with equal accumulated power in a plurality of directions. Alternately, Step 1102 accepts a signal pair including a complex value reference signal (p) at frequency +f and a complex value mirror signal (pm) at frequency −f, where the product (p�pm) is null. For example, i occurrences of the reference signal (p) and the mirror signal (pm) may be accepted, where the sum of the products (pi�pim) is null.
Step 1104 processes the unbiased training sequence, generating a sequence of processed symbols (y) at frequency +f, representing complex plane information in the unbiased training sequence. Step 1106 multiplies each processed symbol (y) by the mirror signal (pm). Step 1108 obtains an unbiased quadrature imbalance estimate Bm at frequency −f.
In one aspect, Step 1102 accepts an unbiased training sequence with a plurality of simultaneously accepted predetermined reference signals and a plurality of simultaneously accepted predetermined mirror signals (pnm). Likewise, Step 1104 generates a plurality of signals (yn) from the corresponding plurality of reference signals (pn). Step 1106 multiplies each received symbol (yn) by its corresponding mirror signal (pnm), and Step 1108 obtains a plurality of unbiased quadrature imbalance estimates (Bnm) from the corresponding plurality of (yn)(pnm) products.
For example, Step 1102 may accept P pilot symbols per symbol period, in a plurality of symbol periods, and Step 1108 obtains P pilot channel quadrature imbalance estimates per symbol period. In this aspect, Step 1103 simultaneously accepts (N−P) quadrature modulated communication data symbols in each symbol period (also see
In another aspect, Step 1102 accepts a temporal sequence of n predetermined mirror signals (pnm) and n predetermined reference signals (pn). Generating the sequence of processed symbols (y) in Step 1104 includes generating a temporal sequence of n processed symbols (yn). Then, obtaining the unbiased quadrature imbalance estimate (Bnm) in Step 1108 includes obtaining a sequence of n quadrature imbalance estimates, and averaging the n quadrature imbalance estimates.
For example (see
In other aspect the method includes the following additional steps. Step 1116 multiplies the processed symbol (y) by a conjugate of the reference signal (p*). Step 1118 obtains an unbiased channel estimate (h) at frequency +f. Processing the unbiased training sequence in Step 1104 includes generating a sequence of processed symbols (ym) at frequency −f. Then, Step 1120 multiplies symbol (ym) by (pm*) to obtain channel estimate hm, at frequency (−f), and Step 1122 multiplies symbol ym by p* to obtain quadrature imbalance estimate B at frequency +f.
If the signal-to-noise ratio (SNR) of (xm) is greater than j (Step 1124), then Step 1126 calculates an imbalance-corrected symbol (z)=y−(Bm/hm*)ym*. Otherwise, Step 1128 sets (z) equal to (y). If the SNR of (x) is greater than j (Step 1130), then Step 1132 calculates (zm)=ym−(B/h*)y*. Otherwise, Step 1134 sets (zm) equal to (ym). Step 1136 uses (z) and (zm) in the calculation of (x) and (xm), respectively. In one aspect, j=1.
The above-described flowchart may also be interpreted as an expression of a machine-readable medium having stored thereon instructions for removing quadrature imbalance errors in received data. The instructions would correspond to Steps 1100 through 1136, as explained above.
Systems, methods, devices, and processors have been presented to enable the removal of quadrature imbalance errors in received data. Examples of particular communications protocols and formats have been given to illustrate the invention. However, the invention is not limited to merely these examples. Other variations and embodiments of the invention will occur to those skilled in the art.
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Would you say there's different techniques on when to/not to use the clutch with a 2-stroke versus a 4-stroke?
Someone asked me the question above in the comments section of my last riding tips, Shift faster without using your clutch, which made me want to write a "Quick Tips" about it.
When people first make the transition from a 2 stroke to a 4 stroke, they try to ride it just like they used to ride their old 2 stroke dirt bike, and quickly realize (hopefully) that 4 strokes are a different beast to tame and that they need to change their riding style a little bit.
So yes, there's definitively different techniques on how and when to use the clutch between a 2 stroke and a 4 stroke. When I switched from 2 strokes to 4 strokes, I had to change my clutching ways because I used to pop the clutch a lot more on a 2 stroke, and that's because you have to keep a 2 stroke in the right revs if you want maximum power.
A 4 stroke, on the other hand, has so much more torque then a 2 stroke that you can ride a gear higher in many places and you don't always need the clutch to find power. You also need to be less aggressive with a 4 stroke, or it will throw you around like a rag-doll and wear you out quick. You have to ride smoother and take advantage of the extra torque and roll the throttle more instead of popping the clutch like a mad man…! All the above is especially true if you're on a 450 4 stroke!!!
Now go out there and practice giving your clutch a break 😀


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- Janelle – (December 10, 2008 at 10:00 PM)
Wow...you guys have first-time parenting syndrome BAD. It's funny, though. Ben and I try to resist it, but we've got it, too.
- Diana – (December 10, 2008 at 10:28 PM)
I love it! She is so cute and yes, she probably is the smartest baby in the world!!! Do you make all her bows? Where do you get the elastic head band stuff? Your cute bows have inspired me!!!
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Votes: 92,656 | Gross: $58.40M
8. Warcraft (2016)
PG-13 | 123 min | Action, Adventure, Fantasy
As an Orc horde invades the planet Azeroth using a magic portal, a few human heroes and dissenting Orcs must attempt to stop the true evil behind this war.
Director: Duncan Jones | Stars: Travis Fimmel, Paula Patton, Ben Foster, Dominic Cooper
Votes: 198,418 | Gross: $47.37M
9. Mission: Impossible - Rogue Nation (2015)
PG-13 | 131 min | Action, Adventure, Thriller
Ethan and team take on their most impossible mission yet, eradicating the Syndicate - an International rogue organization as highly skilled as they are, committed to destroying the IMF.
Director: Christopher McQuarrie | Stars: Tom Cruise, Rebecca Ferguson, Jeremy Renner, Simon Pegg
Votes: 266,605 | Gross: $195.04M
10. Iron Man Three (2013)
PG-13 | 130 min | Action, Adventure, Sci-Fi
When Tony Stark's world is torn apart by a formidable terrorist called the Mandarin, he starts an odyssey of rebuilding and retribution.
Director: Shane Black | Stars: Robert Downey Jr., Guy Pearce, Gwyneth Paltrow, Don Cheadle
Votes: 607,046 | Gross: $409.01M
11. Point Break (2015)
PG-13 | 114 min | Action, Crime, Sport
A young FBI agent infiltrates an extraordinary team of extreme sports athletes he suspects of masterminding a string of unprecedented, sophisticated corporate heists.
Director: Ericson Core | Stars: Edgar Ramírez, Luke Bracey, Ray Winstone, Teresa Palmer
Votes: 47,146 | Gross: $28.78M
12. Never Say Die (2017)
100 min | Comedy, Fantasy
A male UFC boxer switches bodies with the female reporter who exposed his bribes. Now they must help each other win the championship.
Directors: Yang Song, Chiyu Zhang | Stars: Allen Ai, Yuan Chang, Li Ma, Teng Shen
Votes: 245
13. Wolf Warrior II (2017)
126 min | Action, Drama, War
China's deadliest special forces operative settles into a quiet life on the sea. When sadistic mercenaries begin targeting nearby civilians, he must leave his newfound peace behind and return to his duties as a soldier and protector.
Director: Jing Wu | Stars: Jing Wu, Frank Grillo, Celina Jade, Gang Wu
Votes: 2,152 | Gross: $2.34M
14. Rock Dog (2016)
PG | 90 min | Animation, Adventure, Comedy
When a radio falls from the sky into the hands of a wide-eyed Tibetan Mastiff, he leaves home to fulfill his dream of becoming a musician, setting into motion a series of completely unexpected events.
Director: Ash Brannon | Stars: Luke Wilson, Eddie Izzard, J.K. Simmons, Lewis Black
Votes: 2,418 | Gross: $9.40M
15. Kung Fu Panda 3 (2016)
PG | 95 min | Animation, Action, Adventure
Continuing his "legendary adventures of awesomeness", Po must face two hugely epic, but different threats: one supernatural and the other a little closer to his home.
Directors: Alessandro Carloni, Jennifer Yuh Nelson | Stars: Jack Black, Bryan Cranston, Dustin Hoffman, Angelina Jolie
Votes: 95,930 | Gross: $143.53M
16. Bleeding Steel (2017)
Action, Sci-Fi, Thriller | Post-production
Chan stars as a hardened special forces agent who fights to protect a young woman from a sinister criminal gang. At the same time he with feels a special connection to the young woman, like they met in a different life.
Director: Lijia Zhang | Stars: Jackie Chan, Tess Haubrich, Callan Mulvey, Damien Garvey
17. Sky Hunter (2017)
115 min | Action, Drama, Romance
After graduating from flight school, a group of pilots join an elite military group.
Director: Chen Li | Stars: Paul Allica, Andrew Lane Cawthon, George Christopher, A.J. Donnelly
Votes: 96
18. Jue di tao wang (2016)
PG-13 | 107 min | Action, Adventure, Comedy
A detective from Hong Kong teams up with an American gambler to battle against a notorious Chinese criminal.
Director: Renny Harlin | Stars: Jackie Chan, Johnny Knoxville, Bingbing Fan, Eric Tsang
Votes: 13,777
19. Ying xiong (2002)
PG-13 | 107 min | Action, Adventure, History
A defense officer, Nameless, was summoned by the King of Qin regarding his success of terminating three warriors.
Director: Yimou Zhang | Stars: Jet Li, Tony Chiu-Wai Leung, Maggie Cheung, Ziyi Zhang
Votes: 157,689 | Gross: $53.71M
20. Crouching Tiger, Hidden Dragon: Sword of Destiny (2016)
PG-13 | 96 min | Action, Adventure, Drama
A story of lost love, young love, a legendary sword and one last opportunity at redemption.
Director: Woo-Ping Yuen | Stars: Donnie Yen, Michelle Yeoh, Harry Shum Jr., Natasha Liu Bordizzo
Votes: 13,543
21. Tian jiang xiong shi (2015)
R | 127 min | Action, Adventure, Drama
When corrupt Roman leader Tiberius arrives with a giant army to claim the Silk Road, Huo An teams up his army with an elite Legion of defected Roman soldiers led by General Lucius to protect his country and his new friends.
Director: Daniel Lee | Stars: Jackie Chan, John Cusack, Adrien Brody, Si Won Choi
Votes: 14,320 | Gross: $0.07M
22. The Painted Veil (2006)
PG-13 | 125 min | Drama, Romance
A British medical doctor fights a cholera epidemic in a small Chinese village, while being trapped at home in a loveless marriage to an unfaithful wife.
Director: John Curran | Stars: Naomi Watts, Edward Norton, Liev Schreiber, Catherine An
Votes: 81,811 | Gross: $8.06M
23. Step Up 6
100 min | Musical | Post-production
Youth from different social classes in Beijing come together to form China's best dance crew and learn what it really means to be family.
Director: Ron Yuan | Stars: Jade Chynoweth, Janelle Ginestra, Meiqi Meng, Lil Swagg
24. Birth of the Dragon (2016)
PG-13 | 95 min | Action, Biography, Drama
Set against the backdrop of 1960s San Francisco, BIRTH OF THE DRAGON is a modern take on the classic movies that Bruce Lee was known for. It takes its inspiration from the epic and still controversial showdown between an up-and-coming Bruce Lee and kung fu master Wong Jack Man - a battle that gave birth to a legend.
Director: George Nolfi | Stars: Billy Magnussen, Yu Xia, Philip Ng, Jingjing Qu
Votes: 1,594
25. Railroad Tigers (2016)
Not Rated | 124 min | Action, Comedy, War
A railroad worker in China in 1941 leads a team of freedom fighters against the Japanese in order to get food for the poor.
Director: Ding Sheng | Stars: Jackie Chan, Jaycee Chan, Zitao Huang, Kai Wang
Votes: 2,073 | Gross: $0.22M
26. Ex-Baghdad (2019)
Action, Adventure, Thriller | Announced
Two ex-special forces soldiers must escort a group of civilians along Baghdad's "Highway of Death" to the safety of the Green Zone.
Director: Scott Waugh | Stars: Jackie Chan, Sylvester Stallone
27. Yip Man 3 (2015)
PG-13 | 105 min | Action, Biography, Drama
When a band of brutal gangsters led by a crooked property developer make a play to take over a local school, Master Ip is forced to take a stand.
Director: Wilson Yip | Stars: Donnie Yen, Lynn Hung, Jin Zhang, Mike Tyson
Votes: 31,941 | Gross: $2.68M
28. Manhunt (2017)
106 min | Action
Accused of heinous crimes he didn't commit, a prosecutor sets out on a mission to clear his name.
Director: John Woo | Stars: Hanyu Zhang, Masaharu Fukuyama, Stephy Qi, Ji-won Ha
Votes: 125
29. Mei ren yu (2016)
R | 94 min | Comedy, Drama, Fantasy
Shan, a mermaid, is sent to assassinate Xuan, a developer who threatens the ecosystem of her race, but ends up falling in love with him instead.
Director: Stephen Chow | Stars: Chao Deng, Show Lo, Yuqi Zhang, Yun Lin
Votes: 5,804 | Gross: $3.23M
30. Police Story: Lockdown (2013)
Not Rated | 110 min | Action, Crime, Drama
A man looking for the release of a long-time prisoner takes a police officer, his daughter, and a group of strangers hostage.
Director: Ding Sheng | Stars: Jackie Chan, Ye Liu, Tian Jing, Tao Yin
Votes: 6,942
32. Jin ling shi san chai (2011)
R | 146 min | Drama, History, Romance
A Westerner finds refuge with a group of women in a church during Japan's rape of Nanking in 1937. Posing as a priest, he attempts to lead the women to safety.
Director: Yimou Zhang | Stars: Christian Bale, Ni Ni, Xinyi Zhang, Tianyuan Huang
Votes: 41,999 | Gross: $0.01M
33. Dang kou feng yun (2017)
128 min | Action, History
During the 16th century, Japanese pirates proliferate along the Chinese coastline. In 1557, the pirates take over Cengang in Zhejiang. After months of futile advances, Commander Yu (Sammo ... See full summary »
Director: Gordon Chan | Stars: Wenzhuo Zhao, Sammo Kam-Bo Hung, Yasuaki Kurata, Regina Wan
Votes: 420 | Gross: $0.05M
34. Man cheng jin dai huang jin jia (2006)
R | 114 min | Action, Drama, Romance
During China's Tang dynasty the emperor has taken the princess of a neighboring province as wife. She has borne him two sons and raised his eldest. Now his control over his dominion is complete, including the royal family itself.
Director: Yimou Zhang | Stars: Yun-Fat Chow, Li Gong, Jay Chou, Ye Liu
Votes: 38,177 | Gross: $6.57M
35. City of Rock (2017)
140 min | Comedy, Music
A young musician from a small town in China tries to save his town's treasured Rock Park by organizing a charity rock concert.
Director: Chengpeng Dong | Stars: Chengpeng Dong, Coulee Nazha
Votes: 42
36. House of Flying Daggers (2004)
PG-13 | 119 min | Action, Adventure, Drama
A romantic police captain breaks a beautiful member of a rebel group out of prison to help her rejoin her fellows, but things are not what they seem.
Director: Yimou Zhang | Stars: Ziyi Zhang, Takeshi Kaneshiro, Andy Lau, Dandan Song
Votes: 97,040 | Gross: $11.05M
37. The Adventurers (2017)
108 min | Action, Adventure, Crime
The world's top thieves join forces to pull off the heist of a lifetime. But when they find themselves pursued across Europe by a legendary French detective, they'll have to take their game to the next level.
Director: Stephen Fung | Stars: Jean Reno, Qi Shu, Andy Lau, Jingchu Zhang
Votes: 420 | Gross: $0.07M
38. Xiao men shen (2016)
103 min | Animation, Family
There's a crisis in the Chinese Spirit World -- humans don't believe in gods anymore! A Door God, facing unemployment, ventures into the human world to prove his worth, leading to ... See full summary »
Directors: Gary Wang, Terrence Stone, Paulette Victor-Lifton | Stars: Bai-Ke, Mike Birbiglia, Mel Brooks, Dan Fogler
Votes: 408
39. Ming yue ji shi you (2017)
130 min | Drama, War
In Japanese-occupied Hong Kong, a school teacher and her would-be-fiancé link up with Chinese guerrilla fighters, forging their own path to freedom.
Director: Ann Hui | Stars: Xun Zhou, Eddie Peng, Wallace Huo, Deannie Yip
Votes: 255 | Gross: $0.10M
40. Once Upon a Time (I) (2017)
109 min | Drama
An immortal woman reconnects with a love from her past life.
Directors: Anthony LaMolinara, Xiaoding Zhao | Stars: Yang Yang, Yifei Liu, Chun Li, Jin Luo
Votes: 698 | Gross: $0.42M
41. Status Update (2017)
Comedy | Post-production
Ross Lynch stars as Kyle Moore, a teenager who after being uprooted by his parents' separation and unable to fit into his new hometown, stumbles upon a magical app that causes his social media updates to come true.
Director: Scott Speer | Stars: Ross Lynch, Courtney Eaton, Olivia Holt, Harvey Guillen
42. Shock Wave (2017)
119 min | Action, Thriller
When a terrorist who specializes in explosives takes hold of an underground tunnel, he threatens to kill hostages if his demands are not met.
Director: Herman Yau | Stars: Andy Lau, Wu Jiang, Jia Song, Philip Keung
Votes: 915
43. Zhan lang (2015)
Not Rated | 90 min | Action, Crime, Thriller
A Chinese special force soldier with extraordinary marksmanship is confronted by a group of deadly foreign mercenaries who are hired to assassinate him by a vicious drug lord.
Director: Jing Wu | Stars: Jing Wu, Nan Yu, Dahong Ni, Zhu Xiao
Votes: 2,091
44. Red Cliff (2008)
R | 148 min | Action, Adventure, Drama
The first chapter of a two-part story centered on a battle fought in China's Three Kingdoms period (220-280 A.D.).
Director: John Woo | Stars: Tony Chiu-Wai Leung, Takeshi Kaneshiro, Fengyi Zhang, Chen Chang
Votes: 39,121 | Gross: $0.63M
45. Journey to the West (2013)
PG-13 | 110 min | Action, Adventure, Comedy
Tang Sanzang, an aspiring Buddhist hero tries to protect a village from three demons. He develops complex feelings for Miss Duan, the demon hunter who repeatedly helps him, and finally quests to meet the legendary Monkey King.
Directors: Stephen Chow, Chi-kin Kwok | Stars: Zhang Wen, Qi Shu, Bo Huang, Show Lo
Votes: 9,569 | Gross: $0.02M
46. Farewell My Concubine (1993)
R | 171 min | Drama, Music, Romance
The story of two men, who met as apprentices in the Peking Opera, and stayed friends for over 50 years.
Director: Kaige Chen | Stars: Leslie Cheung, Fengyi Zhang, Li Gong, Qi Lü
Votes: 19,590 | Gross: $5.22M
47. IP Man Side Story: Cheung Tin Chi (2018)
Action | Filming
Director: Woo-Ping Yuen | Stars: Jin Zhang, Dave Bautista, Michelle Yeoh, Tony Jaa
48. Jue ji (2016)
Not Rated | 118 min | Animation, Fantasy
An orphan becomes the disciple of a powerful sorcerer and is drawn into a larger conflict among the world's magical elite.
Director: Jingming Guo | Stars: Bingbing Fan, Kris Wu, Cheney Chen, William Wai-Ting Chan
Votes: 512
49. S.M.A.R.T. Chase (2017)
95 min | Action, Adventure, Crime
A washed-up private security agent has to escort a valuable Chinese antique out of Shanghai but is ambushed en route.
Director: Charles Martin | Stars: Orlando Bloom, Lynn Hung, Simon Yam, Hannah Quinlivan
Votes: 25
50. Xi you ji zhi da sheng gui lai (2015)
PG | 89 min | Animation, Action, Adventure
The all-powerful Monkey King once roamed freely between Heaven and Earth, but after angering the Gods, he was imprisoned within an ice cage deep within the mountains. 500 years later, ... See full summary »
Director: Tian Xiao Peng | Stars: Lei Zhang, Zijie Lin, Wenlun Wu, Zirong Tong
Votes: 2,568


text:
Contact Info / Websites
Latest Favorite People
Latest Favorite Movies
Latest Favorite Games
Phoenotopia Rated 4.5000 Stars Journey with Gale on a quest to thwart evil and save her village! Adventure - RPG Gretel and Hansel Part 2 Rated 4.4600 Stars Journey deep into the woods to find your way home... or somewhere else... Adventure - Point 'n Click Treasure Arena Rated 3.5300 Stars Fight against other players in this arcade-style online battle-arena! Action - Shooter - Multidirectional Return to Tolagal Rated 3.9000 Stars A fast paced, turn based roguelike Adventure - RPG Neonball Rated 4.2500 Stars Are you worthy for the use of energy? Action - Other Binding of Isaac DEMO Rated 4.4800 Stars Binding of Isaac is a randomly generated action RPG shooter with heavy Rogue-like elements Action - Other Pause Ahead Rated 4.3400 Stars A challenging and mind bending platformer from the creator of Tower of Heaven Action - Platformer - Puzzle Bosses Forever 2.bro Rated 3.3300 Stars Team up with your bestest bro to climb up the tower fighting bosses forever. Action - Other
Latest Favorite Audio
|Cool Breeze
|Miscellaneous Song
|Ghost & seek
|Video Game Loop
|Stage One
|Video Game Loop
|Octopus War Song
|Video Game Loop
|Soft Edges
|Video Game Loop


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Pushpin OSM, an OpenStreetMap POI Editor for iPhone & iPad
About 6 months ago, at one our of local OSM meetups, we were discussing ways to improve the OpenStreetMap editing experience for casual users. One of the ideas that came out of the discussion was an easy-to-use POI editor for mobile devices. @colemanm and I (@zacmcc) decided to build an app in some of our free time, and it's available today for download.
- Simplified editing interface designed specifically for OpenStreetMap POI's
- Edits are pushed live to OpenStreetMap using your own account over the API
- Bing satellite imagery and openstreetmap.org base layers
- Nominatim search to find places on the map and also to auto-populate address data
- Share your edits to Twitter to spread the word about OpenStreetMap
Like most engineering efforts, it was a lot more work than we originally anticipated. Being OSM contributors ourselves, we were able to selfishly craft the app to do exactly what we wanted it to do. Our main goal was to make collecting detailed POI's as easy as possible. When editing POI's in OpenStreetMap, there are many details that can only be realisitcally collected from the field. In our real-life testing, you typically only have a matter of seconds or minutes to collect a record. When you're waiting for your drinks at dinner, or walking in between stores with friends, you have limited time and patience for remembering the OSM tagging schema. So for most people, the app being easy to use is the difference between using the app and not using it all.
Building the app
When starting this project, it made sense to start with our Fulcrum mobile app as a base for the record editing interface. Fulcrum has all of the plumbing needed for an elegant record editor, like classification sets, choice lists), and conditional logic for controlling field visibility.
The OpenStreetMap tagging model has tons of community-approved tags for describing feature types, so many that even seasoned OSM contributors can't remember if a neighborhood park should be tagged as amenity or leisure. What we did with Pushpin was abstract the complex and numerous tags for point of interest features into a human-readable, searchable list to make it fast and easy to categorize a point. So instead of having to know that amenity=place_of_worship is the proper tag for a church, you can just search for "Church" and find it. Using the map features page and the taginfo service, we tried to include the most commonly used tags for contributing POIs.
Conditional field logic (made possible by Fulcrum's API) is powerful for only showing certain tags when they're relevant. The existence of certain amenities is often dependent on the feature type. Tagging drive_through=yes makes sense for a café or an ATM, but not so much for a public restroom. Pushpin has tons of built-in logic for showing these types of fields when they're relevant, making data contribution faster and cleaner.
State of the Map US
If you'd like to hear more about Pushpin, I will be giving a presentation next week at State of the Map US in Portland.
You can download the app and try it yourself. You can also follow us on Twitter @pushpinapp to let us know what you think, and checkout the shiny new website.


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|» Products
|» Multilayer Co-Ex Bottles
|» Custom Plastic Bottles
Custom Plastic Bottles
Product Code : 28
Product Description
Aimed to provide supreme quality industrial bottles and containers, we are engaged in manufacturing and supplying Custom Plastic Bottles. These bottles are manufactured under the firm direction of the expert professionals using the best quality plastic materials. The materials we use are sourced from the reliable vendors of the market. Our clients can avail these Custom Plastic Bottles from us in different quantity and ranges as per their requirements. We offer these bottles at the market leading price.
Rugged design
Leak proof
Crack resistance
E-17/18, Dsidc Industrial Complex, Nangloi, Delhi - 110041, India
Mr. Deepak Gupta (Director)
Mr. Ankur Gupta (Director)


text: pay-roll definition October 19, 2017 AZ Dictionary Link to this page noun: A roll or set of individuals is paid, with note of amounts that they are entitled. Related Sources Definition for "pay-roll" A roll or set of individuals is paid,… View More Sentence for "pay-roll" Two weeks later, with the pay-roll… View More How would you define pay-roll? All the definitions on AZdictionary were written by people just like you. Now's your chance to add your own! Your Full Name Your definition Post Definition


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Hatice Demiray
Department of Botany, University of Ege Faculty of Science Section of Biology, İzmir, Turkey
The aim of the present work is to investigate the phytochemical content of the grinded stem drog of Rheum ribes L. (Polygonaceae), and to study the biological antioxidant activity of the above ground part extract of Rheum ribes. This plant is distributed in Eastern Turkey locally known as 'ıskın, Uckun or Usgun'. This is the only species of Rheum growing in Turkey (Cullen, 1996).
Plant extraction was obtained with ethanol maceration. Antioxidant activity investigation was performed by DPPH method. Antioxydant activity was determined as 69, 7626% in stems, 91, 6758% in leaves, 94, 4863% in flowers.
Column eluted with cloroform: methanol (95:5) solvent system. 97 from 101 up to the fractions were combined and a new column was established. Hexane: ethyl acetate: methanol (10:10:2) solvent system was used for the second column. The major ingredient in the collected fractions of 22 to 28 was obtained approximately 80% purity. This fractions were combined and third purification column was established with the solvent sysstem of hexane: ethylacetate: methanol (10:10:0.5) and the major compound were purified. 1H NMR and MS datas of the molecule was shown that molecule was β-sitosterylglucoside-6'-octadecanoate. This molecule is the first record of this species.
Keywords: Rheum ribes, isolation, antioxydant activity, β-sitosteryl, extraction.


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Bringing Interior Luxury to Outdoor Living
New arrivals
Black Marine Canvas Ottoman 60x60x30cm$120.00 – $140.00
Navy Marine Canvas Ottoman 60x60x30cm$120.00 – $140.00
Bora Bora – Black$85.00 – $200.00
Read more about us
Outdoor Interiors is an outdoor decor brand offering high quality fade resistant, water resistant and stain resistant outdoor cushions and outdoor throw rugs. Using Sunbrella fabrics and yarns, our outdoor cushions and throw rugs last the test of time.
Established in 2016, Outdoor Interiors is an exciting new homewares brand specialising in contemporary and unique outdoor homewares using fresh, modern colours and designs reflecting the Australian lifestyle.
With our homes now extending outdoors we would like to offer a luxurious range of cushions and throws specifically designed to be used for all seasons.
Why choose Sunbrella Fabrics
Hear from our happy customers
I just received the cushions! They are really nice, thank you very much for the fast delivery, much appreciated!
The quality of the cushions is amazing and the service is outstanding. Thank you so much Sharni. I'll be purchasing again.
Great to deal with. Cushions are exactly what I ordered and the quality is amazing! Adds a beautiful pop of colour and designer look to my outdoor pool yard. Cushions have spent a lot of time out in the sun in the summer just gone and still hold their colour as new. Thank you.
- We absolutely love our cushions, thank you so much!! We love them so much we'd like to order more.We bought some for outside... but they looked so good we have them inside now!
Thank you so much, I absolutely adore my cushions, the fabric is almost luminous in the sun, the colour is gorgeous, just exquisite, extremely high quality. I totally recommend your beautiful collection of outdoor cushions, a major cut above the rest!! Great product and friendly personalised service, all good!!
I recently purchased the Bora Bora range of cushions for my Gazebo. I absolutely love them. Thank you Sharni for the lovely customer service. Highly recommend you guys.
I recently purchased a set of "Outdoor Interiors" cushions for my outdoor entertaining area. It's been great to finally find some outdoor cushions that not only look great but also feel so soft and luxurious. The wide range of fabric choices meant I could find some beautiful designs to match with my existing décor. The fade & water resistant covers also allow me to leave the cushions out by my pool area without worrying about them fading or getting wet. Great company to deal with. So happy with my purchase!
I am really happy with my outdoor cushions from Outdoor Interiors - they were delivered promptly, they look exactly like the picture and they seem really durable. The colour is a perfect match to our pool and I really like that they're reversible as I'm very indecisive!
Very happy with the quality and the service received, the cushions look fabulous!
Awesome service! I received my cushions within 24 hours. Great furnishing and décor options. Lots of trending colours and patterns to choose from. My cushions are 12 months old. Been through rain, hail and shine. They still are 'sparkling' like brand new. I am ready to get some more! Thoroughly recommend.
I ordered a custom made day bed cover and it arrived fitting perfectly to size and amazing quality. Very happy!


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In a world where clothing stores are everywhere, it's very true that activewear is almost never the focus on most designers' lineup of clothes. The truth is that this market is very out there with big brands already taking ownership of this section of women's clothing. However, a new company online is lining up the best designers in this category to give women only the best activewear out there. Fabletics offers women a monthly subscription where they get access to the best activewear on the planet. It is already being considered a brand that is going to take over Amazon in the specific niche.
Women are loving the fact that they get personal recommendations on the kind of activewear that they want to have for their workouts and days where they are on the go. The brand is highly successful that they are going to create a real life store for women to walk in to. This is going to allow women to get the chance to actually try on the clothes before buying them and even buy the clothes at a later date if they so choose to. It's such a great way to find what you want and get the clothes you need so easily.
Women of any size can find what they want and need within this company. Kate Hudson has clothes that go up as high as XXXL because she knows that women who are just starting in their fitness journey deserve to have clothes that fit them and their needs. When you start out in this company and become a member, you have the option to share your needs and what kind of exercises you're doing. You can even let them in on what you are looking for, so if you need something in your size and fits your types of workouts, they can tailor the recommendations to your needs.
Hudson just loves working with this company. She enjoys empowering women to stay fit and get active, and this company is giving her the chance to find that joy and happiness. Fabletics is ultimately one of the best brands out there. They can give you everything you will ever need, and the best part is the fact Fabletics is a growing brand and there's so many women just discovering this. Join today and enjoy all of their great options. They can give you what you need every month.


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If you'd like to join our volunteer database, please email email@example.com
Indicate whether you would like to volunteer in the UK/France/Greece, and let us know a little about you and what you feel your skills are. (Being cheerful over the course of a long day volunteering is a valuable skill!) Our next trips outside the UK will be from April 2017.
If you are an organisation who would like to partner with us either in the UK or overseas, please contact email@example.com
For media enquiries, please see the page on this website, or email email@example.com
All other enquiries about how to get involved, please email firstname.lastname@example.com
We look forward to hearing from you.


text:
Knightsbridge Leather Chair
Knightsbridge Leather Chair
Product informationKnightsbridge leather operator chair. Features a gas seat height adjustment and fully synchronised tilt to seat and back rest with adjustable tension control.
- Luxury cream bonded leather faced executive armchair
- Light oak colour wooden arms and base
- Removable padded arm covers
- Gas lift seat height adjustment
- Reclining function with tilt tension
- Requires easy self assembly
- 3 Days FREE delivery
|Seat Height
|46 to 55 cm
|Seat Depth
|49 cm
|Seat Width
|51 cm
|Back Height
|66 cm
|Back Width
|52 cm
£166(ex VAT)£199.20(inc VAT)


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2017 New York City Rising Stars: Why They Shine Over the past few months, the StarChefs team took a refresher course in New York dining, visiting more than 130 young professionals from Harlem to Pier A and Red Hook to LIC. And we couldn't be more inspired to live, eat, and drink here right now.Read whole article via www.starchefs.com
The latest information, innovation and inspiration in the world of savory including culinary and snacks.
Join your peers today!
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The Best of the 2016-17 Fancy Food Show Trends Are Here
The Summer Fancy Food Show is back for another 3 days of exciting and cutting...
New York's Star Chefs Dish on Innovation and Inspiration
Innovation & Inspiration: Symrise's 2017 New York Rising Stars Roundtable...


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Organic S'mores Kosher Dessert
Yields (12) Servings
Recipe Description:
This recipe originated from a camping trip with a group of Messianic Jewish friends. The dessert idea was designed to create the traditional S'mores treat, which is most commonly enjoyed at fireside while camping outdoors – but to prepare them using a recipe and manner that was both "kosher" and as healthy as possible.
Typically, the terms "healthy" and "dessert" do not usually go together – nor does an "organic" prepared food necessarily mean that it is also "kosher" – (See our text: Cooking with Christ – COOKBOOK – for better details) – This tasty treat however is a very close equivalent for both.
- (1) package of Matzah Crackers *(Passover approved if possible).
- (1) package of all-natural Carob chocolate (usually found as "chips").
- (1) package of organic Marshmallows (limited shelf life – may be ordered from health food stores / *Kosher Marshmallows are also available at specialty stores).
- 1 – 1 1/2 cups all-natural Bee Honey (locally harvested if possible).
- 1/4-1/2 cup freshly ground all-natural Cinnamon (NOT prepackaged in a container).
*These are approximates based on individual use and preference (there may be left-overs).
Preparation: (a camp fire is nice – but an oven will do)
- Break Matzah crackers into the selected size for individual servings.
- Separate quantities of the Marshmallows and Carob chips into a sufficient amount to cover one cracker in a layer of each.
- Coat each Matzah cracker with a layer of Honey and generously sprinkle Cinnamon on top.
- Apply one layer of Marshmallow and one layer of Carob chips onto a honey and cinnamon-coated cracker – place a second coated cracker on top to form a "sandwich".
- COOK until contents are sufficiently melted (by preference) – Do not burn the crackers!
CAMP FIRE – some people place all the ingredients together and sandwich them between the crackers – then heat moderately in a grated holder using the warmth of the camp fire. Otherwise (to avoid being a bit messy), the Marshmallows may be heated separately (on a stick/skewer) – taking them once slightly melted and pressing in the Carob Chips, to then sandwich between the crackers – ready to serve.
OVEN (Preheat to 300 °F) – Use all the ingredients as noted above, sandwiched in between the crackers – Then, heat slowly in the oven until desired melting has occurred – Remove from oven and serve warmed.
Category: Desserts


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London really knows how to nurture young design talent. With many support opportunities for emerging brands, London has made its mark on the fashion map for showcasing some of the most innovative and directional designer collections in the world. The British Fashion Council (BFC) has been supporting young designers for several seasons in conjunction with TOPMAN, and today the organization announced this season's ten emerging menswear talents who will receive NEWGEN MEN support, sponsored by TOPMAN, and will showcase their SS17 collections at London Collections Men in June.
The selected designers are given support to stage a catwalk, salon show, presentation or an installation. Three designers will be receiving NEWGEN MEN support for the first time: recent Central Saint Martins graduate Kiko Kostadinov, Phoebe English, and MAN alumni Wales Bonner in addition to seven returning designers: Alex Mullins, Bobby Abley, Cottweiler, Craig Green, Diego Vanassibara, Liam Hodges, and PIETER.
In addition to receiving showcasing opportunities, the recipients are given financial support and business mentoring. Designers may make use of the financial support to grow or strengthen any aspect of their business, or towards the implementation of their shows, presentations and installations.
LC:M Takes place June 10-13 2016