UE-specific reference signals are also supported for spatial multiplexing on antenna ports 7 and 8. These reference signals are utilized for PDSCH demodulation, if the PDSCH transmission is asso- ciated with the corresponding antenna port. They are transmitted only on the resource blocks upon which the corresponding PDSCH is mapped. The UE-specific reference signals are not transmitted in resource elements (k,l) on which one of the physical channels or physical signals other than UE- specific reference signal are transmitted using resource elements with the same index pair (k, 1), regardless of their antenna port p. Positioning reference signals are only transmitted in downlink subframes configured for posi- tioning reference signal transmission. If both normal and MBSFN subframes are configured as positioning subframes within a cell, the OFDM symbols in an MBSFN subframe configured for positioning reference signal transmission use the same cyclic prefix as that used for the first subframe. Otherwise, if only MBSFN subframes are configured as positioning subframes within a cell, the OFDM symbols configured for positioning reference signals in these subframes use the extended cyclic prefix. The positioning reference signals are transmitted on antenna port 6 and are not mapped to resource elements (k,l) allocated to physical broadcast, primary, and secondary synchronization channels, regardless of their antenna port p. Moreover, these reference signals are only defined for sub-carrier spacing Af = 15 kHz. Figures 9-71 and 9-72 illustrate the mapping of downlink reference signals to antenna ports 0, 1, 2, 3, 4, 5, 7, and 8 [107]. The downlink MBSFN reference signals consist of known reference symbols inserted every other sub-carrier in the 3rd, 7th, and 11th OFDM symbols of subframe in the case of 15 kHz sub-carrier spacing and extended cyclic prefix. Two types of reference signals are used in the uplink: demodulation reference signals (embedded in each PUCCH and PUSCH transmission and use the same bandwidth as cont