Signaling Design and Algorithms for Grant-Free Multiple Access

在智能设备上运行的许多应用程序生成或请求零星的数据包。未来的无线通信系统需要适应这样的设备，并且还为诸如物联网之类的新兴网络提供连接。对于这样的零星数据，正交资源分配或基于请求批准的多址方案是低效的。需要设计一种新型的免授权多址接入机制，该机制允许大量设备共享通信介质以用于递送不频繁的和小尺寸的分组数据。期望的特征包括容纳大量用户的能力、高带宽效率、高可靠性、低延迟和高能量效率。此外，还希望传输可以是异步的，对多径传播和多普勒频移具有鲁棒性，并且在接收机处要求低的处理复杂度。考虑到这一需求，本项目的目标是为这种上行链路多址传输设计新颖的信令方案和高效可靠的检测算法。该项目将设计非正交多址接入方案，包括基于线性预编码的多址接入和编码多址接入，消除了信令和调度开销的需要。低复杂度的检测算法将结合无线通信的特点，包括信道衰落和差错控制编码。所设计的方案和接收机算法的性能将使用理论分析和仿真进行评估。由此产生的新的多址接入方案和检测算法可以提高未来无线网络的效率和吞吐量，并将用于物联网和城域网等应用。

Many applications running on smart devices generate or request sporadic data packets. Future wireless communication systems are required to accommodate such devices and also provide connectivity for emerging networks such as the Internet of Things. For such sporadic data, orthogonal resource allocation or request-approval based multiple access schemes are inefficient. There is need for designing a new type of grant-free multiple access mechanism that allow a large number of devices to share the communication medium for the delivery of infrequent and small-sized packet data. Desirable features include the ability to accommodate a large number of users, high bandwidth efficiency, high reliability, low latency, and high energy efficiency. It is also desirable that the transmissions can be asynchronous, be robust to multipath propagation and Doppler frequency shift, and require low processing complexity at the receivers.With this need in mind, the objective of the project is to design novel signaling schemes for such uplink multiple access transmissions and efficient and reliable detection algorithms. The project will design non-orthogonal multiple access schemes including linear precoding based multiple access and coded multiple access that eliminate the need of signaling and scheduling overhead. Low-complexity detection algorithms will be developed that incorporate features of the wireless communications including channel fading and error control coding. The performance of the designed schemes and receiver algorithms will be evaluated using theoretical analysis and simulations. The resulted novel multiple access schemes and detection algorithms can improve the efficiency and throughput of future wireless networks and will be useful for applications such as Internet of Thing and metropolitan area networks.