Hua Chao

Dirty Paper Coding with phase reshaping: New integration scheme for broadcast and unicast

This paper proposes a new integration scheme for broadcast and unicast in future OFDM system based on Dirty Paper Coding (DPC) to release the orthogonal resource allocation limitation to systems today. Based on the proposed DPC integration architecture, we focus on one-dimensional DPC to optimize the unicast throughput as well as guarantee the coverage of broadcast. It is shown that there is inevitable precoding loss of Tomlinson-Harashima precoding (THP) and structured DPC (SDPC) as they only consider signal amplitude for DPC encoding. The proposed DPC method, called as DPC with phase reshaping (DPC-PR), establishes a connection between DPC and phase reconstruction at the receiver. For QPSK case, link level simulation results prove that DPC-PR outperforms SDPC up to 4dB in AWGN channel. System level performance is also investigated in this paper where unicast applies DPC with known interference of broadcast and broadcast works on single frequency network (SFN) manner. Performances without DPC integration are shown for comparison.

Cooperative broadcasting schemes for LTE-A

In LTE E-MBMS, the fundamental technique is single frequency network (SFN), which simplifies the design of receiver. Under the architecture of SFN, the spectral efficiency is constrained by the maximum transmission power of the base station. According to the evaluation results of LTE E-MBMS, the maximum achievable spectral efficiency is around 1bit/s/Hz, however which can not meet the LTE-A requirement. For further improvements, one of the promising techniques is cooperative communication. However, the current cooperative schemes are difficult to be standardized due to the complexity and network management issues. In this paper, we present some practical cooperative schemes which can be adopted in LTE-A.