Section: 10.2.7.1.2 Mapping to resource elements
Content: The same antenna port shall be used for all symbols of the narrowband primary synchronization signal within a subframe. UE shall not assume that the narrowband primary synchronization signal is transmitted on the same antenna port as any of the downlink reference signals. The UE shall not assume that the transmissions of the narrowband primary synchronization signal in a given subframe use the same antenna port, or ports, as the narrowband primary synchronization signal in any other subframe. The sequences shall be mapped to resource elements in increasing order of first the index and then the index in subframe 5 in every radio frame. For resource elements overlapping with resource elements where cell-specific reference signals according to clause 6.10 are transmitted, the corresponding sequence element is not used for the NPSS but counted in the mapping process.