High-Density Random Access for High-Speed Satellite Data Services

高速卫星数据服务的高密度随机接入

• 批准号: RGPIN-2015-04931
• 负责人: Schlegel, Christian
• 金额: $ 1.82万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680750
• 关键词: Density; Random; Access; Speed; Satellite

In recent years there has been a strong resurgence in interest in satellite communications. The European Space Agency (ESA), for example is investigating satellite-based wireless data services using multi-spot, high-capacity geo-stationary satellites. Such a system will require a satellite throughput capacity on the order of a terabyte/s in order to be economically competitive with ground-based wireless services. ***A modern satellite, operating with multiple spot beams, is capable of covering a large geographic area and servicing a very large number of users. Difficulties arise when the traffic through the satellite increases to the point where basic access and communications methods no longer suffice to service the data demand. This difficulty is compounded by the long round-trip delays between transmissions on the up-link and reception of acknowledgements on the down-link, which prevents rapid coordination between transmitters. The receiver also needs to be able to resolve signal collisions and be able to estimate and track channel conditions for a multitude of user terminals. These challenges represent a are the major focus of the proposed research project.***The most recent variations of random access contention resolution transmit multiple copies of a data packet in randomly distributed time slots throughout a transmission frame. This approach statistically increases the rate of packet collisions, but the probability that at least one copy of a packet is received collision-free is increased. This packet can then be cancelled from the other time slots where it was also transmitted, allowing for iterative peel-off decoding of the entire frame. Theoretical studies have shown that this method can achieve 80% of the single user capacity for practical scenarios, which represents a vast improvement over the 37% achievable with a basic slotted ALOHA protocol. ***However, the channel itself, is a multiple access channel, and as such it has a theoretical capacity which is superior to that of any multiplexed channel. Exploitation of this advantage requires the incorporation of joint detection principles. Multi-packet reception(MPR) will be addressed with iterative interference cancellation, which has recently been shown to be able to approach the multiple access channel capacity in theory. However, substantial problems remain before such MPR receivers can be deployed. This project focuses on the challenges that arise when realistic channel propagation models are used, in particular channels with highly dynamic behavior. It is anticipated that the fundamental results from this work will lead to increased utilization of spectral resources and robustness of networks. We have been collaborating with the German Aerospace Institute (DLR), and this grant will accelerate this collaboration, and lead to a strong research program in resource-efficient data communications at Dalhousie University.**

近年来，人们对卫星通信的兴趣再度强烈起来。例如，欧洲空间局（ESA）正在研究使用多点、高容量地球静止卫星的基于卫星的无线数据服务。这样一个系统将需要大约1 tb /s的卫星吞吐量，以便在经济上与地面无线服务竞争。使用多个点波束的现代卫星能够覆盖很大的地理区域并为非常多的用户提供服务。当通过卫星的通信量增加到基本接入和通信方法不再足以满足数据需求时，就会出现困难。上行链路上的传输和下行链路上的确认接收之间的长往返延迟使这一困难更加复杂，这妨碍了发射机之间的快速协调。接收机还需要能够解决信号冲突，并能够估计和跟踪众多用户终端的信道条件。这些挑战代表了拟议研究项目的主要焦点。***最近的随机访问争用解决方案在传输帧中以随机分布的时隙传输数据包的多个副本。这种方法在统计上增加了数据包碰撞率，但至少有一个数据包副本被接收到无碰撞的概率增加了。然后，这个数据包可以从它也传输的其他时隙中取消，从而允许对整个帧进行迭代剥离解码。理论研究表明，该方法在实际场景中可以实现80%的单用户容量，这比基本的开槽ALOHA协议所能实现的37%有了很大的提高。然而，信道本身是一个多路访问信道，因此它的理论容量优于任何多路复用信道。利用这一优势需要结合联合探测原则。多包接收（MPR）将通过迭代干扰消除来解决，这在理论上已被证明可以接近多址信道容量。然而，在部署这种MPR接收器之前，还存在一些实质性问题。本项目侧重于使用真实通道传播模型时出现的挑战，特别是具有高度动态行为的通道。预计这项工作的基本结果将提高频谱资源的利用率和网络的鲁棒性。我们一直在与德国航空航天研究所（DLR）合作，这笔拨款将加速这种合作，并在达尔豪斯大学（Dalhousie University）开展资源高效数据通信方面的强大研究项目