Throughput-Oriented Non-Orthogonal Random Access Scheme for Massive MTC Networks
Throughput-Oriented Non-Orthogonal Random Access Scheme for Massive MTC Networks
复制标题
面向吞吐量的海量MTC网络非正交随机接入方案
DOI：
10.1109/tcomm.2019.2957767
复制
发表时间：
2020-03-01
影响因子：
8.3
通讯作者：
Cheng, Julian
中科院分区：
文献类型：
--
作者：
Wang, Yichen;Wang, Tao;Cheng, Julian
机器类型通信（MTC）技术使设备之间能够直接通信，在实现物联网方面起着重要作用。然而，大量的MTC设备可能导致严重的冲突。其结果是，网络吞吐量降低，接入延迟增加。为了解决这个问题，面向吞吐量的非正交随机接入（诺拉）方案被提出用于大规模机器类型通信（mMTC）网络。具体地，通过采用标记可访问性（PA）技术，选择相同PA的多个MTC设备（MTCD）可以被区分并被视为非正交多址（NOMA）组，这使得多个MTCD能够通过在功率域中复用来共享相同的物理上行链路共享信道以用于传输。采用Sukhatme的经典理论和特征函数法来描述优化问题。目标是在功率回退因子、NOMA组中包含的MTCD数量和成功传输概率的约束下，最大化吞吐量。基于粒子群优化算法，有效地解决了公式化的优化问题。所导出的解决方案可以用于调整接入类别限制因子，使得更多的MTCD可以获得接入机会。此外，还开发了一种低复杂度的次优解，它可以在高数据速率要求下达到接近PSO的性能。仿真结果表明，该方案能有效地提高网络性能，并与现有方案进行了比较。
Machine-type communications (MTC) technology, which enables direct communications among devices, plays an important role in realizing Internet-of-Things. However, a large number of MTC devices can cause severe collisions. As a result, the network throughput is decreased and the access delay is increased. To address this issue, a throughput-oriented non-orthogonal random access (NORA) scheme is proposed for massive machine-type communications (mMTC) networks. Specifically, by employing the technique of tagged preambles (PAs), multiple MTC devices (MTCDs) choosing the same PA can be distinguished and regarded as a non-orthogonal multiple access (NOMA) group, which enables multiple MTCDs to share the same physical uplink shared channel for transmissions by multiplexing in the power domain. The Sukhatme's classic theory and the characteristic function approach are adopted to formulate an optimization problem. The aim is to maximize the throughput subject to the constraints on the power back-off factor, the number of MTCDs included in a NOMA group, and the successful transmission probability. Based on the particle swarm optimization (PSO) algorithm, the formulated optimization problem is efficiently solved. The derived solution can be used to adjust the access class barring factor such that more MTCDs can obtain the access opportunities. Moreover, a low-complexity suboptimal solution is also developed, which can achieve near-PSO performance under high data rate requirement. Simulation results show that the proposed scheme can efficiently improve the network performance and comparison is made with the existing schemes.