Toward Massive, Ultrareliable, and Low-Latency Wireless Communication With Short Packets
Toward Massive, Ultrareliable, and Low-Latency Wireless Communication With Short Packets
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DOI：
10.1109/jproc.2016.2537298
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发表时间：
2016-09-01
影响因子：
20.6
通讯作者：
Popovski, Petar
中科院分区：
文献类型：
--
作者：
Durisi, Giuseppe;Koch, Tobias;Popovski, Petar
在高速无线系统设计中的大多数最新进展都是基于信息理论原理，该原理演示了如何有效地传输长数据分组。然而，即将到来的无线系统，特别是第五代（5G）系统，将需要支持使用短分组的新型业务类型。例如，短分组表示由机器对机器（M2M）通信中涉及的传感器和其他设备生成的最常见的业务形式。此外，存在新兴应用，其中小分组被期望携带应当以低延迟和超高可靠性接收的关键信息。当前的无线系统没有被设计为支持短分组传输。例如，当前系统的设计依赖于元数据（控制信息）与实际信息有效载荷相比具有可忽略的大小的假设。因此，使用启发式方法传输元数据不会影响整体系统性能。然而，当分组较短时，元数据可以具有与有效载荷相同的大小，并且用于传输元数据的常规方法可能是非常次优的。在本文中，我们回顾了信息论的最新进展，它提供了管理短数据包传输的理论原则。然后，我们将这些原理应用于三个示例性场景（双向信道、下行链路广播信道和上行链路随机接入信道），从而示出当分组短时如何优化控制信息的传输。这些例子所带来的见解表明，新的原则是需要设计的无线协议支持短数据包。这些原则将对系统设计产生直接影响。
Most of the recent advances in the design of highspeed wireless systems are based on information-theoretic principles that demonstrate how to efficiently transmit long data packets. However, the upcoming wireless systems, notably the fifth-generation (5G) system, will need to support novel traffic types that use short packets. For example, short packets represent the most common form of traffic generated by sensors and other devices involved in machine-to-machine (M2M) communications. Furthermore, there are emerging applications in which small packets are expected to carry critical information that should be received with low latency and ultra-high reliability. Current wireless systems are not designed to support short-packet transmissions. For example, the design of current systems relies on the assumption that the metadata (control information) is of negligible size compared to the actual information payload. Hence, transmitting metadata using heuristic methods does not affect the overall system performance. However, when the packets are short, metadata may be of the same size as the payload, and the conventional methods to transmit it may be highly suboptimal. In this paper, we review recent advances in information theory, which provide the theoretical principles that govern the transmission of short packets. We then apply these principles to three exemplary scenarios (the two-way channel, the downlink broadcast channel, and the uplink random access channel), thereby illustrating how the transmission of control information can be optimized when the packets are short. The insights brought by these examples suggest that new principles are needed for the design of wireless protocols supporting short packets. These principles will have a direct impact on the system design.