Chapter 14
The Near-Capacity Differentially Modulated Cooperative Cellular Uplink
14.1 Introduction
In point-to-point communication systems using a single antenna or co-located multiple antennas, it is feasible to achieve a high spectral efficiency by approaching Shannon’s capacity limit with the aid of channel coding, as argued in Chapter 10. However, in contrast to the well-understood limitations of point-to-point single-user transmissions, researchers are only beginning to understand the fundamental performance limits of wireless multi-user networks, such as, for example, the cooperative cellular uplink considered in Chapters 12 and 13. To be more specific, in the scenarios of the uncoded DAF as well as DDF cooperative cellular uplinks, the best achievable BER performance can be approached by optimizing both the power control and the cooperating user selection, as discussed in Chapter 13. Naturally, the resultant cooperative system’s performance is expected to be better than that of non-cooperative transmission. The attainable transmit diversity gains as well as path-loss reduction achieved by the cooperative relay-aided system were considered in Chapter 13, which translate into substantially enhanced robustness against fading for a given transmit power, or into a significantly reduced transmit power requirement for the same BER performance. However, the transmit diversity gains or cooperative diversity gains promised by the cooperative system considered are actually achieved ...
