SCMA for downlink multiple access of 5G wireless networks
SCMA for downlink multiple access of 5G wireless networks
复制标题
DOI：
10.1109/glocom.2014.7037423
复制
发表时间：
2014-04
期刊：
影响因子：
--
通讯作者：
Hosein Nikopour;Eric Yi;A. Bayesteh;K. Au;Mark Hawryluck;H. Baligh;Jianglei Ma
中科院分区：
文献类型：
--
作者：
Hosein Nikopour;Eric Yi;A. Bayesteh;K. Au;Mark Hawryluck;H. Baligh;Jianglei Ma
稀疏码多址（SCMA）是一种新型的频域非正交多址技术，可以提高无线接入的频谱效率。利用SCMA，不同的输入数据流被直接映射到不同的多维食谱的码字，其中每个码字表示扩展传输层。多个SCMA层共享OFDMA的相同时频资源。码字的稀疏性使得通过迭代消息传递算法（MPA）实现近最优检测成为可能。多层检测的这种低复杂度允许过度的码字过载，其中复用层的维度超过码字的维度。过载因子沿着层的调制编码级别的优化提供了更灵活和有效的链路自适应机制。另一方面，SCMA的信号扩展特性可以改善链路自适应性，从而减少有色干扰。在本文中，开发了一种技术，使多用户SCMA（MU-SCMA）的下行链路无线接入。用户配对、功率共享、速率调整和调度算法被设计为提高重负载网络的下行链路吞吐量。还评估了SCMA扩展对于轻负载网络的优势。
Sparse code multiple access (SCMA) is a new frequency domain non-orthogonal multiple-access technique which can improve spectral efficiency of wireless radio access. With SCMA, different incoming data streams are directly mapped to codewords of different multi-dimensional cookbooks, where each codeword represents a spread transmission layer. Multiple SCMA layers share the same time-frequency resources of OFDMA. The sparsity of codewords makes the near-optimal detection feasible through iterative message passing algorithm (MPA). Such low complexity of multi-layer detection allows excessive codeword overloading in which the dimension of multiplexed layers exceeds the dimension of codewords. Optimization of overloading factor along with modulation-coding levels of layers provides a more flexible and efficient link-adaptation mechanism. On the other hand, the signal spreading feature of SCMA can improve link-adaptation as a result of less colored interference. In this paper a technique is developed to enable multi-user SCMA (MU-SCMA) for downlink wireless access. User pairing, power sharing, rate adjustment, and scheduling algorithms are designed to improve the downlink throughput of a heavily loaded network. The advantage of SCMA spreading for lightly loaded networks is also evaluated.