Section: 6.1.3.10 Data Volume and Power Headroom Report MAC Control Element
Content: The Data Volume and Power Headroom Report (DPR) MAC control element is identified by the MAC PDU subheader used for the CCCH MAC SDU, as specified in table 6.2.1-2. It does not add any additional subheader and is always placed before the CCCH MAC SDU. DPR MAC control element is not included in the calculation of the L field in the MAC PDU subheader for the CCCH MAC SDU. It has a fixed size and consists of a single octet defined as follows (figures 6.1.3.10-1 and 6.1.3.10-1a): - Data Volume (DV): The Data Volume field identifies the total amount of data available across all logical channels and of data not yet associated with a logical channel after all MAC PDUs for the TTI have been built. The amount of data is indicated in number of bytes. It shall include all data that is available for transmission in the RLC layer, in the PDCP layer, and in the RRC layer; the definition of what data shall be considered as available for transmission is specified in TS 36.322[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Link Control (RLC) protocol specification ]  [3], TS 36.323[ Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification ]  [4] and TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [8] respectively. The size of the RLC and MAC headers are not considered in the buffer size computation. The length of this field is 4 bits. The values taken by the Data Volume field are shown in Table 6.1.3.10-1; - Power Headroom (PH): This field indicates the power headroom level. The length of the field is 2 bits or 4 bits. The reported PH and the corresponding power headroom and extended power headroom levels are shown in Table 6.1.3.10-2 and Table 6.1.3.10-2a, respectively, below (the corresponding measured values in dB can be found in TS 36.133[ Evolved Universal Terrestrial Radio Access (E-UTRA); Requirements for support of radio resource management ]  [9]); - R: reserved bit, set to "0". Figure 6.1.3.10-1: Data Volume and Power Headroom Report MAC control element Figure 6.1.3.10-1a: Data Volume and Power Headroom Report MAC control element for Extended Power Headroom level reporting Table 6.1.3.10-1: Data Volume levels for DV Table 6.1.3.10-2: Power Headroom levels for PH Table 6.1.3.10-2a: Extended Power Headroom levels for PH