用FPGA实现低功耗、低成本的RRH解决方案

以往，基于MIMORRH（射频拉远技术）系统邻近天线的逻辑电路都是用高湍、高级FPGA来实现。这些高端FPGA的成本和功耗一般都很高，往往迫使厂商牺牲设计的灵活性，并试图转换为昂贵的ASIC。     

浅析新建无线基站的几方面应对措施

随着移动通信的快速发展和人们对天线辐射抗拒心理的不断增强,无线基站的选址和建设难度越来越大,本文从天线的外观美化、射频拉远技术的应用以及联合建站三个方面详细介绍了新时期无线基站建设的有效应对措施,从而达到提高建站效率和质量,降低建站成本的目的.     

TD-LTE基站射频设计技术

作为TD-LTE网络覆盖末端的射频基站,RRH对无线网络覆盖和整体网络性能影响巨大。文章针对TDD系统特点,结合当前射频技术发展情况,介绍TD-LTE射频基站系统,并对TD-LTE射频基站的关键技术以及发展方向进行研究与分析。     

Design and Implementation of Dynamic High-Speed Switches in Super Base Station Architectures

Novel centralized base station architectures integrating computation and communication functionalities have become important for the development of future mobile communication networks.Therefore,the development of dynamic high-speed interconnections between baseband units(BBUs)and remote radio heads(RRHs)is vital in centralized base station design.Herein,dynamic high-speed switches(HSSs)connecting BBUs and RRHs were designed for a centralized base station architecture.We analyzed the characteristics of actual traffic and introduced a switch traffic model suitable for the super base station architecture.Then,we proposed a data-priority-aware(DPA)scheduling algorithm based on the traffic model.Lastly,we developed the dynamic HSS model based on the OPNET platform and the prototype based on FPGA.Our results show that the DPA achieves close to 100%throughput with lower latency and provides better run-time complexity than iOCF and HE-iSLIP,thereby demonstrating that the proposed switch system can be adopted in centralized base station architectures.     

On the interdependence between kinetics of friction-released thermal energy and the transition in wear mechanisms during sliding of metallic pairs

Sliding of complying solids is often associated with the release of thermal energy. This energy accumulates within the mechanically affected zone (MAZ) of the rubbing pair. The accumulation of thermal energy within the MAZ tends to maximize the potential energy at the interface. Now, since a maximized potential energy renders the sliding system unstable, one (or both) materials will respond in a manner that consumes (dissipates) part or all of the accumulated energy in order to re-establish system stability or at least equilibrium. The material response may be in many forms: oxidation, crack initiation, wear debris generation, transition in wear mechanism, etc. As such, one may consider that these processes are intrinsic responses by the material to dissipate energy. Moreover, many of these responses are triggered at different stages of rubbing according to the balance between the rate of external thermal energy release (which is a factor of the nominal operation parameters) and the rate of thermal energy accumulation—RTEA (which is mainly a function of thermal transport properties of the rubbing pair). An interesting feature of this view is that the later quantity—RTEA—is directly related to the ability of the particular solid to dissipate thermal loads. This quantity, which is termed here as the heat dissipation capacity (HDC), is directly related to the state of blockage of energy dissipation paths within the rubbing solid. The objective of this paper is therefore to study the relation between the change in the HDC of a sliding solid and the transition in the mechanism of wear. It is shown that there exists an inverse correlation between the change in the HDC and the transition in the mechanism of wear. Moreover, it is also shown that a so-called ratio of residual heat (RRH, representing the ratio between the actual thermal load and the part of that load that is not dissipated by the solid) is a significant parameter that influences the magnitude and mechanism of wear. The findings are applied to explain the wear behavior of two tribo systems: a titanium (Ti-6Al-4V) sliding on itself and sliding on a steel (AISI M2) counterpart.     

地铁隧道UMTS无线网络覆盖解决方案浅析

通过对地铁隧道无线覆盖设计中几种常用信号源和天馈系统的简要定性分析,以及信号源和天馈系统不同组合建网方案的定量的计算,文章提出了一种在建网初期用户数量及业务量较低情况下,利用宏蜂窝基站和RRH组合的地铁隧道覆盖解决方案。     

CLB: a multilevel co-operative load balancing algorithm for C-RAN architecture

The Fifth-Generation (5G) cellular and wireless communication envisage to integrate multiple technologies to provide a wide range of applications. The rapid growth of Information and Communication Technology (ICT) needs a common cellular platform to increase the network’s extensibility and adaptability. The Cloud Radio Access Network (C-RAN) offers a scalable and flexible Base Station (BS) architecture for the next-generation wireless and mobile networks, where the BS functionality is split into a distributed radio unit known as Remote Radio Head (RRH) and a Centralized BaseBand Unit (C-BBU). To further make the C-BBU scalable and flexible, the baseband signal processing is carried out over a virtualized platform. The load at the RRH and C-BBU can vary from under-loaded to overloaded conditions which increase the power consumption and degrade the Quality-of-Service (QoS) of the C-RAN. In this paper, we formulate under-loaded and overloaded conditions at the RRH and the C-BBU, and propose a Co-operative Load Balancing (CLB) algorithm for handling the cellular traffic in real-time under different load conditions. The proposed CLB aims to maximize the utilization of hardware resources at the RRH and C-BBU. The CLB algorithm is compared with CDI, CZ, NDLB, DLB in the first phase for the RF load balancing. In the second phase of simulation, CLB is compared with the FCFS, IWRR, OLB, GP and TLB algorithms for server (C-BBU) load balancing. The parameters considered for comparison are: User Entity (UE) waiting time, blocking probability and processing time at the RRH and the C-BBU. Simulation results show that the use of co-operative load balancing technique improves the QoS in the C-RAN by reducing the blocking probability and UE waiting time. The CLB algorithm is validated with LTE TU-Vienna and cloudSim simulators for the RRH and the C-BBU, respectively.     

阿尔卡特朗讯WCDMA射频拉远解决方案

针对WCDMA介绍了射频拉远技术的基本概念,并从集成度、网络建设和维护等方面介绍了射频拉远的特点,最后简单说明全球应用案例。