Enhancements for the Higher SINR Region: UL OFDMA and 256-QAM —
In small cell deployments, especially in the aforementioned frequency-separated deployments between wide and local areas, it is expected that a relatively high SINR can often be observed at the eNB or UE receiver due to lower intercell interference compared to macrocellular deployments. Therefore, link-level performance enhancements for the higher SINR region (e.g., higher than 20 dB) is beneficial in improving the user-experience throughput in local area. Higher-order modulation such as 256- quadrature amplitude modulation (QAM) can be effective in improving the throughput performance in a high SINR region. For UL enhancements in a higher SINR region, the benefits of OFDMA compared to current single-carrier frequency-division multiple access (SC-FDMA) need to be revisited. Also, hybrid access between OFDMA and current SC-FDMA , as shown in Fig. 4b, can be considered for UL radio access.