论文标题
晶格代码多访问：体系结构和有效算法
Lattice-Code Multiple Access: Architecture and Efficient Algorithms
论文作者
论文摘要
本文研究了基于$ K $ - 用户晶格代码的多访问（LCMA）方案。每个用户设备（UE）用实用的晶格代码编码其消息，我们建议使用$ 2^m $ -ary \ emph {ring code}，并带有符号的biostive映射到$ 2^m $ -PAM。编码调节的信号以其指定的签名序列扩散，并且所有$ k $ ues同时发送。 LCMA接收器选择一些整数系数，计算UES消息的\ emph {Integer Linear Compinations}（INTEGER线性组合}（ILCS）的相关$ K $流，然后从这些ILC流中重建所有UES的消息。为了执行此操作，我们提出了新的有效LCMA \ emph {软检测}算法，该算法计算了晶格上ILC的A后验概率。复杂性的订单不超过$ o（k）$，适合于大型$ k $的大量访问。软检测输出将转发到$ k $环形代码解码器，这些解码器采用$ 2^m $ y-ary信念传播来恢复ILC流。 To identify the optimal integer coefficients of the ILCs, a new ``%\emph{bounded independent vectors problem}" (BIVP) is established. We then solve this BIVP by developing a new \emph{rate-constraint sphere decoding} algorithm, significantly outperforming existing LLL and HKZ lattice reduction methods. Then, we develop optimized signature sequences of LCMA使用我们开发的算法使用新的目标转换算法。单用户解码操作避免了连续干扰取消和迭代检测的实施问题。
This paper studies a $K$-user lattice-code based multiple-access (LCMA) scheme. Each user equipment (UE) encode its message with a practical lattice code, where we suggest a $2^m$-ary \emph{ring code} with symbol-wise bijective mapping to $2^m$-PAM. The coded-modulated signal is spread with its designated signature sequence, and all $K$ UEs transmit simultaneously. The LCMA receiver choose some integer coefficients, computes the associated $K$ streams of \emph{integer linear combinations} (ILCs) of the UEs' messages, and then reconstruct all UEs' messages from these ILC streams. To execute this, we put forth new efficient LCMA \emph{soft detection} algorithms, which calculate the a posteriori probability of the ILC over the lattice. The complexity is of order no greater than $O(K)$, suitable for massive access of a large $K$. The soft detection outputs are forwarded to $K$ ring-code decoders, which employ $2^m$-ary belief propagation to recover the ILC streams. To identify the optimal integer coefficients of the ILCs, a new ``%\emph{bounded independent vectors problem}" (BIVP) is established. We then solve this BIVP by developing a new \emph{rate-constraint sphere decoding} algorithm, significantly outperforming existing LLL and HKZ lattice reduction methods. Then, we develop optimized signature sequences of LCMA using a new target-switching steepest descent algorithm. With our developed algorithms, LCMA is shown to support a significantly higher load of UEs and exhibits dramatically improved error rate performance over state-of-the-art multiple access schemes such as interleave-division multiple-access (IDMA) and sparse-code multiple-access (SCMA). The advances are achieved with just parallel processing and $K$ single-user decoding operations, avoiding the implementation issues of successive interference cancelation and iterative detection.
