Protocol for integration of voice and data over frame-based PRMA

A novel protocol for the integration of voice and data over frame based packet reservation multiple access (F-PRMA) is proposed. The voice-priority scheme is employed to provide a quality-of-service (QOS) guarantee for the voice service. Numerical results indicate that a significant amount of data traffic can be supported with a much lower mean packet delay than is achieved with previous protocols, and voice capacity is also improved because it is not necessary to transmit the header message with every packet     

A new protocol for the integration of voice and data over PRMA

In packet reservation multiple access (PRMA) the receiver in the mobile terminal is required to listen continuously to monitor the acknowledgment messages broadcasted at the end of every time slot. A new scheme for the integration of voice and data based on PRMA is proposed. The voice and the data subsystems are logically separated. The total available bandwidth is divided into three regions-voice information, voice contention, and data regions. The available bandwidth is dynamically partitioned between the above three regions subject to the fulfillment of the quality of service (QoS) requirements of the voice users. The voice subsystem has been modeled as a Markov chain and an exact analytical method used to compute the voice packet dropping probability is described. A nonlinear programming problem is formulated to optimize the bandwidth allocated for the data users. Solutions to this nonlinear programming problem that are very close to optimum have been obtained heuristically. Numerical results indicate that a significant amount of data traffic can be supported without sacrificing the voice capacity of the system     

Performance evaluation of a modified PRMA protocol for joint voiceand data packet wireless networks

In this paper, a modified version of the packet reservation multiple-access (PRMA) protocol is proposed to provide spatially dispersed voice and data user terminals wireless access to a base station over a common short-range radio channel. An analytical approach is presented in order to derive system performance in terms of mean data message delay and voice packet dropping probability. A suitable permission probability design is also proposed to enhance system performance. Performance comparisons with an extension of the PRMA protocol to voice data systems previously reported in literature are shown to highlight the better behavior of this approach     

语音通信中传输隐藏数据的技术研究与系统设计

为了在不影响语音通信效果的前提下,在语音通信的同时实现传输有用的隐藏数据,提出了一种在发射端采用改进的回声隐藏算法嵌入隐藏数据,而在接收端采用倒谱算法检测原始语音信号和隐藏数据的方法,能够解决一般传输中可靠性差、误码率高的问题.最后构建了以Sun Spot为核心的硬件平台系统,借助Spot的无线传感器、ARM920T、CC2420无线通讯器件和创新的Squawk JAVA虚拟机,通过JAVA语言编程和嵌入技术实现语音信号的采集、隐藏数据的嵌入、混合信号的同步传输和信号的检测还原等功能.实验证明了改进回声算法的有效性和系统的可行性,该系统为工业应用提供参考.     

Performance of a joint CDMA/PRMA protocol for mixed voice/datatransmission for third generation mobile communication

A joint code-division multiple-access/packet-reservation multiple-access (CDMA/PRMA) technique is proposed and investigated as a candidate for an uplink protocol for third generation mobile communication systems. Access to the radio channel is controlled such that compared to random access CDMA, interference variance is reduced and throughput increased. Mixed voice/data traffic is investigated for an isolated cell only, whereas voice-only traffic is also investigated in a cellular environment with a regular hexagonal cell structure. Intercell interference is assumed to be Gaussian, and only the average interference level is considered     

Performance of PRMA: a packet voice protocol for cellular systems

Equilibrium point analysis is used to evaluate system behavior in a packet reservation multiple access (PRMA) protocol based network. The authors derive the probability of packet dropping given the number of simultaneous conversations. The authors establish conditions for system stability and efficiency. Numerical calculations based on the theory show close agreement with computer simulations. They also provide valuable guides to system design. Because PRMA is a statistical multiplexer, the channel becomes congested when too many terminals are active. For a particular example it is shown that speech activity detection permits 37 speech terminals to share a PRMA channel with 20 slots per frame, with a packet dropping probability of less than 1%     

Performance evaluation of a packet voice system

A study is made of statistical multiplexing of voice packets from a number of packetized voice sources onto a single channel. Each source alternates between talkspurt (active period) and silence, and packets are generated during active periods only. The packets are buffered (in a finite size buffer) when transmission capacity is not available. An embedded Markov chain model is adopted to analyze the system and a numerical technique is presented to compute system performance. Simulation results validate the analysis     

Performance analysis of joint voice-data PRMA over random packeterror channels

We consider a joint voice-data packet reservation multiple-access (PRMA) system with transmission errors. Two analysis methods are presented. The first is a combined Markov and equilibrium point analysis. In this method, equilibrium point analysis is used to obtain the equilibrium number of backlogged data terminals, while Markov analysis is used to compute the stationary state probability distribution, assuming the number of backlogged data terminals is equal to the equilibrium value. The second is a Markov analysis using an approximate marginal distribution of backlogged data terminals. System performance measures, namely, voice packet dropping probability, data packet delay, and throughput, are derived in the presence of transmission errors. Computation complexity and accuracy are compared for the two analysis methods. Simulation results are also presented for comparison with analysis results, and good agreement is observed, especially when the packet header error rate is small     

话音和数据在远距离光纤通信系统中的传输

设计了一种基于FPGA的用于传输话音和RS232串口数据的远距离光纤通信系统.该系统分别由话音信号处理电路、RS232接口电路、光电信号处理模块和FPGA控制电路组成.系统具有传输话音清晰、数据传输误码小、传输距离远以及安装方便等特点.     

语音题库系统的设计和实现

题库系统是计算机辅助测验系统的一种重要形式，本文研制和开发了一个《语音题库系统》，能更好的进行英语听力试题的管理及听力测试，系统不仅具有以往传统题库的特点，同时也结合了英语听力试题的特点，在实际应用中证明具有非常好的实用性。     

电话语音信箱系统的需求分析与总体设计

本文主要在学校业务背景分析和需求调查的前提下,作了本语音信箱项目的需求分析,同时按照系统分层等设计原则,提出了总体设计,给出了软件系统架构。语音系统中所用到的技术,都是当前业已成熟的技术,只要较好地集成已有软件平台和和可靠的硬件设备,即可成功地实现一套稳定的系统。系统建设的成本较低,维护费用少,项目的投资少而见效快,为电话语音信箱业务的开展提供强有力的支撑。     

Design and performance evaluation of a packet voice system

A packet voice network has been designed using adaptive delta modulators. Tests were performed to examine the effects of packet length and packet loss rate on digital voice intelligibility. The packet voice network was simulated using a SLAM network model to find queue size requirements as a function of packet size, delay distribution, and expiring time out. The queuing strategy is investigated in order to minimize total information loss during channel acquisition delays.     

声音导引电动车系统硬件设计

声音导引系统．是基于无线通信技术的新型导引系统．可以应用于新型智能机器人控制系统．这种声音控制机器人的运动方式将有着广阔的应用前景。将声音导引无线通信技术与单片机结合起来,设计了声音导引电动车系统,通过接收平台接收到声音时间不同,计算出指定位置,通过无线传输数据控制电动车到达指定位置。用单片机完成整个系统的控制。通过单...     

Performance evaluation of packet data services over cellular voice networks

In this paper we develop a Markov chain modeling framework for throughput/delay analysis of data services over cellular voice networks, using the dynamic channel stealing method. Effective approximation techniques are also proposed and verified for simplification of modeling analysis. Our study identifies the average voice call holding time as the dominant factor to affect data delay performance. Especially in heavy load conditions, namely when the number of free voice channels becomes momentarily less, the data users will experience large network access delay in the range of several minutes or longer on average. The study also reveals that the data delay performance deteriorates as the number of voice channels increases at a fixed voice call blocking probability, due to increased voice trunking efficiency. We also examine the data performance improvement by using the priority data access scheme and speech silence detection technique.     

基于AMBE-3000的多路语音数据处理系统

简介AMBE-3000基本功能及AMBE算法,提出利用数字信号处理芯片和EPM7128搭建TDM电路对两片FIFO和四片缓存FLASH完成电路控制,达到了基于单片语音处理芯片的多路语音数据记录实时工作目的,具有语音处理芯片利用率提高、系统复杂度降低以及操作简单易行等优点.讨论了多路信号采集、多片缓存FLASH与单片AMBE-3000在TMS320F2812系统控制下稳定工作所需要的技术条件,以及系统的电磁兼容性能分析.     

Performance modeling and evaluation of data/voice services in wireless networks

Application-level performance is a key to the adoption and success of the CDMA 2000. To predict this performance in advance, a detailed end-to-end simulation model of a CDMA network is built to include application traffic characteristics, network architecture, network element details using the proposed simulation methodology. We assess the user-perceived application performance when a RAN and a CN adopt different transport architectures such as ATM and IP. To evaluate the user-perceived quality of voice service, we compare the end-to-end packet delay for different vocoder schemes such as G.711, G.726 (PCM), G.726 (ADPCM), and vocoder bypass scheme. By the simulation results, the vocoder bypass scenario shows 30% performance improvement over the others. We also compare the quality of voice service with and without DPS scheduling scheme. We know that DPS scheme keep the voice delay bound even if the service traffic is high. For data packet performance, HTTP v.1.1 shows better performance than that of HTTP v.1.0 due to the pipelining and TCP persistent connection. We may conclude that IP transport technology is better solution for higher FER environment since the packet overhead of IP is smaller than that of ATM for web browsing data traffic, while it shows opposite effect to the small size voice packet in RAN architecture. We show that the 3G-1X EV-DO system gives much better packet delay performance than 3G-1X RTT. The main conclusion is that end-to-end application-level performance is affected by various elements and layers of the network and thus it must be considered in all phases of the development process. Jae-Hyun Kim He received the B.S., M.S., and Ph.D. degrees, all in computer science and engineering, from Hanyang University, Ansan, Korea, in 1991, 1993, and 1996 respectively. In 1996, he was with the Communication Research Laboratory, Tokyo, Japan, as a Visiting Scholar. From April 1997 to October 1998, he was a post-doctoral fellow at the department of electrical engineering, University of California, Los Angeles. From November 1998 to February 2003, he worked as a member of technical staff in Performance Modeling and QoS management department, Bell laboratories, Lucent Technologies, Holmdel, NJ. He has been with the department of electrical engineering, Ajou University, Suwon, Korea, as an assistant professor since 2003. His research interests include QoS issues and cross layer optimization for high-speed wireless communication. Dr. Kim was the recipient of the LGIC Thesis Prize and Samsung Human-Tech Thesis Prize in 1993 and 1997, respectively. He is a member of the Korean Institute of Communication Sciences (KICS), Korea Institute of Telematics and Electronis (KITE), Korea Information Science Society (KISS), and IEEE. Hyun-Jin Lee received the B.S. degree in electrical engineering from Ajou University, Suwon, Korea, in 2004, and is working toward the M.S. degree and Ph. D. degree in electrical engineering at Ajou University. He has been awarded Samsung Human-Tech Thesis Prize in 2004. His research interests QoS, especially network optimization and wireless packet scheduling. He is a member of the KICS. Sung-Min Oh received the B.S. and M. S. degrees in electrical engineering form Ajou University, Suwon, Korea, in 2004, and is working toward the Ph. D. degree in electrical engineering at Ajou University. His research interests QoS performance analysis and 4G network. He is a member of the KICS. Sung-Hyun Cho received his B.S., M.S., and Ph.D. in computer science and engineering from Hanyang University, Korea, in 1995, 1997, and 2001, respectively. From 2001 to 2005, he has been with Samsung Advanced Institute of Technology, where he has been engaged in the design and standardization of MAC and upper layers of B3G, IEEE 802.16e, and WiBro systems. He is currently a MAC part leader in the telecommunication R&D center of Samsung Electronics. His research interests include 4G air interface design, radio resource management, cross layer design, and handoff in wireless systems.     

Integrating data traffic into a CDMA cellular voice system

Part one of this paper analyzes the effects of data traffic integration into a CDMA cellular voice system. The figure of merit used for the quality of service seen by the voice users is measured by the probability of blocking. The CDMA system under consideration is a power controlled, cellular architecture in which blocking occurs when the total interference level exceeds the background noise level by 10 dB [1]. It is shown that the introduction of data can be done at little or no increase in the probability of blocking on the voice users. In part two we propose and analyze a protocol which achieves the efficient integration of data by maximizing the utilization of the resources and minimizing the delay experienced by the voice users. The proposed protocol admits data traffic into the CDMA cellular system based on the current aggregate voice interference level, and allows for the efficient integration of voice and data without degrading the quality of service for the delay-critical voice traffic. A Markovian model for this protocol is developed, evaluated and compared to computer simulation results.     

Numerical analysis of joint CDMA/PRMA protocol based on equilibriumpoint analysis

Numerical expressions to assess the performance of a joint direct sequence code division multiple access/packet reservation multiple access (CDMA/PRMA) protocol are presented. Simulation of CDMA/PRMA systems with narrowbeam antennas is also applied to support the proposed technique     

Interaction of TCP and data access control in an integrated voice/data CDMA system

This paper considers the interaction between a proposed data access control scheme and the standardized error recovery schemes on the radio link of a voice/data CDMA system. A data access control scheme for combined voice-data CDMA systems has been proposed and studied in previous literature. The scheme aims to maintain a certain target voice signal to interference ratio (SIR); this is achieved by controlling the data load according to the measured voice SIR. The data users are allowed to transmit in a radio-link time slot with a certain permission probability, which is determined by the base station based on the measured voice SIR in the previous slot. As per the IS-99 standards, however, data transmission operates under the framework of TCP, which is a higher level end-to-end protocol. The TCP data unit, called a segment, is typically equivalent to several tens of physical layer frames; hence, a segment transmission takes up several tens of slots. Due to changes in the number of voice users in talkspurt (which occur on a time scale shorter than a segment transmission time), the slot level data access control scheme can introduce significant variability in the segment transmission time. The effect of such variability on the TCP timers, which operate at the segment level, is of interest. In this paper, an approximate upper bound on the data throughput, taking the presence of TCP into account, is computed. The results provide one with an insight into the interaction of the access control scheme with TCP; they also give practical pointers as to choosing suitable parameters and operating points for the scheme. This revised version was published online in June 2006 with corrections to the Cover Date.     

Performance analysis of a PRMA protocol suitable for voice and datatransmissions in low Earth orbit mobile satellite systems

Mobile satellite systems (MSSs) are expected to play a significant role in providing users with communication services worldwide. In such a context, low Earth orbit (LEO) satellite constellations seem to be a good solution to attain a global coverage and to allow the use of low-power lightweight mobile terminals. This paper analyzes the performance of a novel medium access control (MAC) scheme suitable for applications in LEO-MSSs, named packet reservation multiple access with hindering states (PRMA-HS), that has been derived by proper modifications of the well-known PRMA protocol. We envisage a mixed traffic with voice sources and data sources with different quality of service (QoS) requirements. The good behavior of the proposed PRMA-HS scheme is validated by extensive comparisons with the classical PRMA protocol. Finally, it is shown that PRMA-HS efficiently supports integrated voice and data traffic in LEO-MSSs