High-Throughput and Area-Efficient Rotated and Cyclic Q Delayed Constellations Demapper for Future Wireless Standards

Abstract

Applying rotated and cyclic Q delayed (RCQD) modulation on the transmitter side improves the performance of the receiver in case of fading channel conditions along with erasures. However, the complexity of demapping in the receiver increases significantly to achieve this elevated performance. Many low complexity demapping solutions are available but few are actually implemented in hardware. Recently, new constellation rotation angles and associated simplified demapping technique with better performance for fading channel conditions along with erasure scenarios has been proposed. In this paper, we propose a novel demapper architecture model that exploits these latest simplifications. Moreover, a joint demapper implementation is proposed, which can demap the symbols from different constellations using full or simplified demapping algorithm to achieve best throughput in terms of LLR/sec. Compared to state-of-the-art implementations of RCQD demappers, significant hardware reductions are demonstrated encouraging the use of RCQD modulation in future wireless communication applications.