【作者】 王海；

【导师】 王新；

【作者基本信息】 复旦大学 ， 计算机应用技术， 2014， 硕士

【摘要】 随着通信技术的迅猛发展,飞速膨胀量成了下一代无线网络中最关键的问题。而中继以其性能佳、易于拓展部署方便等优势在新一代网络标准中占有一席之地。本文挑选了三个典型的场景-WiMAX,数据中心网络和蜂窝网络-作为中继性能研究的承载场景。对于目前采用多跳中继技术的WiMAX网络,本文提出DPRP (Dual-Path Relay Placement)以优化中继的布局。DPRP通过两条平行对称的多跳中继链路获得空间复用。对于给定的衰减因子,当用户的频谱效率超过一定界限时,相比SPRP (Single-Path Relay Placement)策略DPRP更加节省中继。分析得知,用户的频谱效率越高,DPRP的优势就越明显。对单个蜂窝而言,如果将SPRP和DPRP结合使用,必将大大降低中继带来的开销。数据中心网络布线复杂且开销较大,促使人们引入无线中继来缓解机架的拥塞问题。研究者在无线数据中心领域已取得很多成果,但目前为止还没人将目光锁定在功率分配问题上。所以本文便提出动态的功率分配策略,该策略简单易行,并且可以大大提升无线数据中心网络的吞吐量。仿真结果也很好地验证了动态功率策略的确优于传统的等功率发送策略。在蜂窝网络中,数据流量的合理管理越来越受重视。存在的首要问题是一部分用户流量不够用,另一部分却用不完。基于此本文设计出一个协助传输系统以优化所有用户的体验,前提假设是具有剩余流量的用户愿意协助其余用户下载一些东西,然后将下载的数据通过WiFi重传给请求用户。为了保证系统的实现,第一步提出一个基于LT码的UDP协议,该协议可以保证协助的正常进行；接下来设计了一个实际系统来进行验证,结果表明用户可以更有效地管理自己的数据,而且还可以大大提升自己的下载速率。更多还原

【Abstract】 With the rapid development of communication technology, the huge and fast expantion of the traffic has become the most outstanding issue in the future wireless networks. Relay, with the advantage of its good performance and conve-nience in deployment, has become a part of this mobile networks. In this thesis, we choose three typical scenarios-WiMAX Networks、Data Center Networks and Cellular Networks to study the performance of relays.In WiMAX, we propose DPRP (Dual-Path Relay Placement) to improve the efficiency of relay station placement. DPRP can achieve efficient spatial reuse by two independent parallel transmission paths. For a given attenuation coefficient, DPRP needs less RSs than Single-Path Relay Placement (SPRP) when the SS’s Spectrum Efficiency exceeds a certain threshold. The analysis proves that the higher the Spectrum Efficiency is, the greater the difference is between the relay’s number of two models. If the new model is integrated with the SPRP model, the total number of RSs required per cell will decrease a lot.Data Center Networks (DCNs) suffer from the complex wiring issues, which has motivated us to consider a wireless solution. Researchers have made great achievements in wireless DCNs. But so far, no research has focused on the power allocation for wireless DCNs. In this paper, we consider dynamic power allocation for wireless DCNs. An optimal power allocation procedure with low complexity is derived to maximize the total throughput of all live wireless transmissions. To demonstrate the effectiveness of our strategy, extensive simulation study is carried out and the results show that our proposed allocation scheme significantly outperforms the existing equal power allocation scheme.Following fast growth of cellular networks, increasingly users have drawn attention on the contradiction between dynamic user traffic and fixed data plans. So in this paper, we build a new data plan sharing system, which is based on the scenario that some smartphone users have surplus data traffic and are willing to help others download data. To realize this system, we first propose a LT-code based UDP protocol. It is robust to transmission errors and encourages more concurrent transmissions. It also can be implemented easily with low cost. Then we design a real environment experiment and the results show that users in our system not only can manage their surplus data plan more efficiently, but also achieve a higher speed download rate.更多还原