Toward the software realization of a GSM base station

Advances in processor and analog-to-digital conversion technology have made the software approach an increasingly attractive alternative for implementing radio-based systems. For mobile telephony base stations, the advantages with the new architecture are obvious: great cost savings by using one transceiver per base transceiver station (BTS) instead of one per channel, tremendous flexibility by moving system-specific parameters to the digital part, and allowing the support of a wide range of modulation and coding schemes. This paper considers the software implementation of a GSM BTS, and analyzes the performance of each of its radio interface modules. The performance of each software module is evaluated using both a % CPU metric and a processor-independent metric based on SPEC benchmarks. The results can be used to dimension systems, e,g., to estimate the number of software-based GSM channels that can be supported by a given processor configuration, and to predict the impact of future processor enhancements on BTS capacity. Two novel aspects of this work are the portability of the software modules and the platform-independent evaluation of their computational requirements     

High-performance DSPs

The processing delay is a serious constraint for speech communication. A one-way end-to-end delay of more than 150 ms can severely degrade the quality of real-time conversations. The components of the total system delay includes the speech frame size, the look ahead, other algorithmic delays, multiplexing delay, processing delay for computation, and transmission delay. At the transcoder rate adaptor unit (TRAU), the only delay that can be manipulated is the processing delay. The TRAUs are generally positioned remote to the base transceiver station (BTS). The channel codec units (CCUs) are located in the BTS. In general, 16 kbit/s traffic channels can be used for full rate speech between the TRAU and BTS. By putting the TRAU remote to the BTS, DSPs for speech coding can be utilized more efficiently to cut system cost. High performance DSPs, such as the Lucent DSP16000, can be used to further cut the cost per speech channel. This article presents an implementation of GSM enhanced full rate (EFR) codec on the Lucent Technologies' DSP16000. The original European Telecommunications Standards Institute (ETSI) C code has been restructured to address the issues of MIPS (million instructions per second), RAM usage, and processing delay. We give a performance overview of vocoder implementations on some existing fixed-point DSPs and discuss the architecture of the DSP16000. Details on how the ETSI C code is restructured are presented. The DSP16210 implementation results are then discussed     

Development of the Base Station Transceiver Subsystem in the CDMA Mobile System

The base station transceiver subsystem (BTS) of the CDMA Mobile System is interfaced to mobile stations over the air and to the wired network through a packet switched interconnection network. The potential benefits of CDMA technology are achieved when the transmitter and the receiver are properly designed and implemented. The physical layer of the air interface at the base station is implemented with the CDMA ASICs and control circuits in the channel card of the BTS. We present the design perspectives and structural illustration of the BTS. Base station modem ASICs and their control to implement the CDMA receiver, baseband and RF signal processing blocks, and BTS controller are described. Elaborate power control is essential to ensure the high capacity which is one of advantages of the CDMA technology. The closed loop reverse link power control and the forward link power control operated in the BTS are described.     

Présentation d’une technique 3D d’accélération de la recherche de rayons application aux télécommunications microcellulaires

Development of telecommunications using mobile phones requires the installation of many base stations (BTS) in order to cover the large number of cells which make up the network. Existing systems (GSM, DSC) use carrier frequencies within the microwave range. Ideally, operators should have simulation software to determine the position of BTS. This software would be used initially to determine the geometric configuration of the cells. The next step would be to optimise the radiation pattern of each BTS antenna. In this article we present a method for determining radioelectric coverage based on image theory adapted to the problem, which is more accurate and less time-consuming than conventional methods.     

虚拟无线电技术及其应用

近年来软件无线电技术已成为无线电通信领域的技术热点。文中首先介绍软件无线电的基本概念、体系结构及其关键技术 ,在此基础上着重探讨软件无线电的发展新趋势虚拟无线电 (virtualradio)技术 ,通过与传统软件无线电技术的比较 ,分析其优势所在 ,并以SpectrumWare系统为例 ,提出了采用虚拟无线电技术实现GSM收发信基站的软件模块设计方法。     

KISS-16V2: a one-chip ASIC DSP solution for GSM

Outlines the requirements for the various digital signal processing functions of the pan-European digital mobile cellular telephone system in terms of computational power and RAM and ROM capacities, and describes a digital signal processor (DSP) solution which is able to integrate all of these digital baseband functions for a hand-held terminal onto one VLSI chip. The KISS-16V2 processor, a low-power CMOS 16-b DSP, is optimized for digital telecommunications, especially for Groupe Speciale Mobile (GSM). A power-down mode together with the capability of memory and multiplier standby operation make this DSP well suited for handheld devices. A design strategy based on the extensive use of cell compilers and synthesis tools reduces the design of further DSP derivations to a minimum.<>     

面向智能家居的嵌入式传感网网关的研究与设计

为了实现家庭内部网路与Internet以及GSM网的互联,提出了一种嵌入式无线智能家居网关系统的设计方案。该网关系统的硬件平台以ARM920T核处理器S3C2440为主处理器,采用ZigBee协议建家庭内部网络,而且通过以太网模块和GSM模块接入外部网络。软件平台采用Linux操作系统,通过交叉编译设计网关的应用程序。最后,以Qtopia Core为嵌入式GUI,进行家庭网关监测应用软件的功能需求分析,设计图形用户界面,实现家庭内部信息的查询。基于ARM9和Linux的嵌入式网关系统,可扩展性强,数据处理速度快,使用简单,能够对家庭网络内部多项环境信息进行监测。     

GSM基站收发信机中的功率放大电路分析

基于爱立信公司的GSM基站收发信机原理,从电路方面对射频放大器进行了匹配分析和稳定性分析,说明了爱立信公司的GSM基站的一些特点.     

Numerical Aspects of MIMO OFDM PHY Layer Applications on SDR Platforms

IEEE 802.11n compliant receivers are composed of a number of functional blocks, each one with a specific computational complexity and requirements for numerical precision. MIMO preprocessing causes a major part of the computational complexity, since it typically consists of operations like QR decompositions or matrix inversions. Hence, it also demands considerable numerical precision, while other parts of the transceiver, e.g. MIMO equalization or OFDM modulation, need significantly less accuracy. Various publications exist on the issue of ASIC design for MIMO preprocessing. However, the increasing variety of mobile communication standards calls for more flexible platforms, implementing the different standards in software, hence called Software Defined Radios (SDRs). This work focuses on achieving bit error rates (BERs) close to floating-point performance while using the limited fixed-point precision typically available on SDR platforms. To that end, several algorithmic enhancements are described that enable a numerically stable MIMO application even on a 16-bit fixed-point platform. These enhancements are implemented on the maturing P2012 platform by ST Microelectronics as proof-of-concept. Execution time as well as error correction performance are discussed as quality indicators of the implementation.     

基于GSM900M升级的EDGE＋＋应用及评估

EDGE＋＋的本质是FDD-LTE技术,可以通过升级农村的GSM900M且在共用现网TD-LTE的核心网、PTN传输网基础上改造完成。硬件上,将GSM900M的RRU替换为EDGE＋＋的RRU,BBU侧增加EDGE＋＋的基带处理板和主控板,GSM900M的天馈资源无需替换。软件上,通过Refarming GSM工具清理出农村的空闲频率5M,升级EDGE＋＋的eNodeB的软件版本,修改GSM900M的BTS的相关模式,联调EDGE＋＋的eNodeB,打通EDGE＋＋的eNodeB到EPC之间的PTN传输通道,完成eNodeB站点业务调测。最后,将EDGE＋＋信号通过支持EDGE＋＋的MiFi或CPE终端转换成Wi-Fi信号,在农村提供Wi-Fi热点。     

A Partial CSI Estimation Approach for Downlink FDD massive-MIMO System with Different Base Transceiver Station Topologies

Massive multiple-input multiple-output (massive-MIMO) is a promising technology for next generation wireless communications systems due to its capability to increase the data rate and meet the enormous ongoing data traffic explosion. However, in non-reciprocal channels, such as those encountered in frequency division duplex (FDD) systems, channel state information (CSI) estimation using downlink (DL) training sequence is to date very challenging issue, especially when the channel exhibits a shorter coherence time. In particular, the availability of sufficiently accurate CSI at the base transceiver station (BTS) allows an efficient precoding design in the DL transmission to be achieved, and thus, reliable communication systems can be obtained. In order to achieve the aforementioned objectives, this paper presents a feasible DL training sequence design based on a partial CSI estimation approach for an FDD massive-MIMO system with a shorter coherence time. To this end, a threshold-based approach is proposed for a suitable DL pilot selection by exploring the statistical information of the channel covariance matrix. The mean square error of the proposed design is derived, and the achievable sum rate and bit-error-rate for maximum ratio transmitter and regularized zero forcing precoding is investigated over different BTS topologies with uniform linear array and uniform rectangular array. The results show that a feasible performance in the DL FDD massive-MIMO systems can be achieved even when a large number of antenna elements are deployed by the BTS and a shorter coherence time is considered.

     

一种短信控制的水浸报警系统设计

为了满足在一些场所的溢水监测需求,利用GSM网络的短信业务实现水浸报警并采用一种算术平均值滤波的软件数字滤波方法抑制电磁干扰。硬件设计中,系统以MSP430单片机为控制器核心,以TC35模块为短信无线收发器,并与水浸检测模块构成了系统的硬件平台。软件设计中,单片机通过UART串口向TC35模块配置AT指令来控制短信的接收与发送,采集水浸检测模块的电压值并存储到单片机寄存器中作为触发报警的条件。实现了短信方式的水浸报警,控制系统的水浸灵敏度调节,添加或删除用户手机号码,以及自定义报警提示内容。系统满足了溢水情况的短信报警需求,具有控制灵活、远程报警的特点。     

GSM over Ethernet

The author reports on how a UK company-with a little help from Category 5 cabling-is helping to realise the commercial potential of the GSM pico base station. ip.access, a Cambridge technology start-up is the supplier of the world's smallest GSM base station, the nanoBTS (base station transceiver), measuring a mere 210 mm by 280mm. It is fully compatible with the ETSI pico base station standard, and has a range of over 500 m in an uncluttered environment, while the in-building range is of the order of 50 m, depending on the building construction materials     

基于单片机的GSM短信收发模块设计

本设计研究如何通过单片机的控制,实现GSM模块接收和发送简单数字、字母的短信。随着科技的发展,GPS和GSM的联合定位装置将给人们带来更大地方便,如何控制GSM模块将接收到的定位数据发送和回收,对后续的数据处理有至关重要的作用。本文使用MSP430单片机通过RS232串口与GsM模块通信,使用标准的AT命令来控制GsM模块实现各种无线通信功能。实验结果表明：该模块能够稳定的将定位数据以短信的方式进行传输。     

A multi‐mode IFFT/FFT processor for IEEE 802.11ac: design and implementation

In this paper, we present 64/128/256/512‐point inverse fast Fourier transform (IFFT)/FFT processor for single‐user and multi‐user multiple‐input multiple‐output orthogonal frequency‐division multiplexing based IEEE 802.11ac wireless local area network transceiver. The multi‐mode processor is developed by an eight‐parallel mixed‐radix architecture to efficiently produce full reconfigurability for all multi‐user combinations. The proposed design not only supports the operation of IFFT/FFT for 1–8 different data streams operated by different users in case of downlink transmission, but also, it provides different throughput rates to meet IEEE 802.11ac requirements at the minimum possible clock frequency. Moreover, less power is needed in our design compared with traditional software approach. The design is carefully optimized to operate by the minimum wordlengths that fulfill the performance and complexity specifications. The processor is designed and implemented on Xilinx Vertix‐5 field programmable gate array technology. Although the maximum clock frequency is 377.84 MHz, the processor is clocked by the operating sampling rate to further reduce the power consumption. At the operation clock rate of 160 MHz, our proposed processor can calculate 512‐point FFT with up to eight independent data sequences within 3.2~μs meeting IEEE 802.11ac standard requirements. Copyright © 2015 John Wiley & Sons, Ltd.     

基于GSM模块的远程控制和报警系统

介绍了一种基于GSM/GPRS网络的无线远程控制和报警系统,详细阐述了系统的组成结构和软硬件设计。该系统采用GSM/GPRS模块发送接收短消息和彩信,从而实现对家居安全状况的远程监控。选用多种传感器采集家居信息,通过无线收发模块传递到主控制器,运用信息融合技术,获得可靠的报警信息。业主接到报警信息后,回复短信可以控制和处理现场情况,达到保证家居安全和防盗的目的。     

LTE/GSM多模基站收发信台数字中频模块故障诊断的新方法

针对LTE/GSM多模基站收发信台（BTS）开发中FPGA数字中频模块故障诊断的需求,开发 了一种基于以太网数据通信接口,利用Matlab软件直接存取FPGA内部寄存器值,并且可以连 续采集数字中频模块内部关键节点大块数据的软硬件协 处理方法,从而快速定位数字中频信号链路的调测问题并帮助排除故障。这种诊断方法无缝 集成在FPGA设计中,可以在BTS测试开发的各个阶段采用,不需要额外设备及接口。在LTE/G SM MSR（Multi-Standard Radio）项目中利用该诊断技术完成了数字中频模块上下行信号 处理链路频谱异常等故障的诊断与定位。     

Efficient receiver structure for GSM mobile radio

The paper describes a receiver structure for the digital GSM mobile radio which is suitable for implementation using a DSP processor. The simulation results show that proposed simplifications have minor influence on the receiver performance and drastically reduce its computational complexity.     

无线局域网中的OFDM收发器ASIC及其设计

本文介绍了目前越来越普及的无线局域网中的正交频分复用(Orthogonal Frequency Division Muhiplex)收发器专用集成电路ASIC芯片的设计和实现。在简要综述了应用于无线局域网收发器技术的ASIC结构和工作原理后，着重分析了其基于面向对象的设计方法，并且给出了实际OFDM收发器ASIC设计中需要关注的几个问题。采用C 语言实现的高层次ASIC设计EDA工具，可以对芯片的算法和结构进行快速仿真验证，简化了OFDM收发器等运算密集型ASIC的设计。     

An efficient DMT modem for the G.LITE ADSL transceiver

In this paper, a discrete multitone (DMT) modem for the client side G.LITE ADSL transceiver is presented. The DMT modem is one of the most computationally intensive parts in the transceiver. In the design, computational complexity and operational regularity were traded-off to decide suitable fast Fourier transform (FFT)/Inverse FFT and frequency-domain equalization (FEQ) algorithms. We used the radix-2 real FFT and the normalized LMS that guarantees an equal convergence per tone. Based on operational community between FFT and FEQ, a resource-shared design was implemented. Datapath of the DMT modem comprises one real multiplier and two real adders, which are connected in parallel and flexibly used under control. The designed modem has been coded in VHDL and synthesized with 0.35-/spl mu/m standard CMOS cell. Synthesis results exhibit that the proposed system can provide a cost-effective solution to asymmetric digital subscriber line devices owing to its small design area.