RESIDENT: a reliable residue number system-based data transmission mechanism for wireless sensor networks

Retransmission is the most common data transmission mechanism in wireless sensor networks, and can improve data transmission reliability via the acknowledgement mechanism. However, the simple acknowledgement retransmission is associated with some negative factors such as data delay, low throughput among others. To overcome the shortcomings of the retransmission mechanism, redundancy coding is introduced to wireless communications, which has been widely applied in 4G communication. Unfortunately, not all redundant erasure codes are suitable for wireless sensor networks, as nodes’ energy, processing power, and storage capacity are all limited. Moreover, we also need to consider data transmission delay. Therefore, to improve data transmission reliability, we must take into account the complexity of algorithm, data transmission delay, node energy consumption, and other factors. In this article, we propose a REliable reSIDuE number system-based data transmission mechanism (RESIDENT) for WSNs, which can improve data transmission reliability via hybrid automatic repeat requests in hop-by-hop scenarios. In order to decrease the complexity of decoding, we present our algorithm and the proof of correctness, and report the performance using extensive set of simulation experiments. Our simulation results show that RESIDENT exhibits a good performance when compared to the previous studies, not only in terms of reliable data transmission, but also in end-to-end delay and energy consumption.     

Residue number system-based multicarrier CDMA system for high-speedbroadband wireless access

This correspondence is concerned with a new method to enhance the bandwidth efficiency of a multicarrier CDMA system by using a residue number based representation for information symbols. The residues are mapped into a set of orthogonal sequences and are transmitted in parallel. A new modulation scheme is proposed to increase the data rate further by combining residue number representation, PSK/QAM modulation, orthogonal spreading and multicarrier modulation. The performance of the proposed system is evaluated in a frequency selective Rayleigh fading channel via extensive simulations. The present correspondence discusses the design issues associated with the system together with the performance results     

Multi-phased VSG CDMA with level clipping for high-rate transmission systems

In this letter, a multi-phased CDMA system employing a variable spreading gain (VSG) approach is proposed for high-rate applications, based on four algorithms for selecting a multi-code set. From simulation results, in addition to simple receiver structure thanks to level clipping, the multi-phased VSG CDMA system provides an high bit rate transmission, while maintaining an acceptable performance degradation.     

FAULT-TOLERANT PERFORMANCE OF DATA TRANSMISSION MODELS BASED ON REDUNDANT RESIDUE NUMBER SYSTEM

Fault-tolerant data transmission models based on the redundant residue number system are proposed in this paper; they can transmit data correctly between two ends unless the residue errors exceed the error-correction capability. The expressions for the probability of error are presented when the channel noise is additive Gaussian noise and each branch is M-ary orthogonal signaling modulation. The expressions of the probabilities of undetected and uncorrected error are also obtained when the redundant residue number system are single error-checking and single error-correcting model, respectively.     

采用CPCI总线的通用高速数传接收机

针对高速数传技术的快速发展和广泛应用,提出了一种DSP实现CPCI总线的高速数传通用接收机实现方案.该设计兼容模数混合和全数字硬件输入接口,采用ADC采样率在线设置和程序动态加载技术,可实时完成对不同码速率和不同调制编码方式数据源的解调译码.对450 Mbit/s和600 Mbit/s两种高速数传性能进行了测试,结果表明其接收机解调损失分别小于1 dB和1.5 dB,满足工程应用需求.     

A data transmission scheme for CDMA wireless networks based onIS-95

Data integration into the existing cellular voice systems is an attractive approach since it can reduce an initial implementation cost of the data network and can provide voice/data integrated services. In this paper, we propose a data transmission scheme for code-division multiple-access (CDMA) cellular voice systems. The CDMA systems under consideration include IS-95 digital cellular systems using the 800-900-MHz band and J-STD-008 personal communications systems using the 1.8-2.0-GHz band. The proposed protocol and control schemes are designed for real systems based on IS-95 rather than conceptual systems and require no modifications to the existing voice mobile stations (MSs). Using computer simulation, the performance of voice and data users is evaluated. As a result, we show that the proposed scheme well meets our design goals, which are that the data transmission scheme should not only provide a good data performance, but also have little effect on the voice performance     

Congestion control schemes for reverse link data transmission in multimedia CDMA systems

We investigate the congestion control schemes for reverse link in code division multiple access multimedia systems. We propose four schemes according to the control bit setting methods at base and the rate decision schemes in mobiles. With the proposed schemes, all mobiles control their transmission power and rate simultaneously. As the aggregate effect, the cell-wide congestion control is accomplished. The performance of systems with the proposed schemes are evaluated using computer simulation and compared with each other. Under a congested situation, the proposed schemes guarantee the priority of real-time traffic over non-real-time traffic and prevent an excessively high error rate for real-time services. We describe and evaluate the proposed schemes under the system model assumption based on 1xEV-DO and cdma2000. However, the proposed schemes can be also applied to wide-band code division multiple access systems with minor modification.     

A time-orthogonal CDMA high-speed uplink data transmission scheme for 3G and beyond

In 3G systems, the achievable data rates and capacity on the uplink are much smaller than the downlink data rates and capacity due to the nonorthogonal nature of the CDMA uplink. In this article, we present a new time-orthogonal CDMA approach called high-speed uplink data burst transmission mode. The concept is based on slot-synchronized slot-orthogonal transmissions whereby high-speed data transmissions take place in slots orthogonal to the slots used for physical layer control signaling and low-data-rate transmission such as resource requests. Using this approach, very high data rates and capacity are achieved during data burst transmission because of the availability of high signal-to-interference-plus-noise ratio, resulting from the orthogonal nature of the transmissions. Simulation results show that the uplink spectral efficiency of the proposed scheme is approximately four times better than that achieved with the existing 3G systems     

高速DWDM通信技术及进展

综述了高速DWDM(密集波分复用)系统中的关键技术,包括QPSK(四相相移键控)、8QAM(8进制正交幅度调制)和16QAM(16进制正交幅度调制)等新型调制格式、超低损耗光纤/拉曼放大和新型光集成器件,并分析、比较了这些关键技术对DWDM系统传输产生的不同影响。在此基础上,介绍了近年来DWDM大容量传输的一些成功试验。试验表明,这些关键技术有着广阔的应用前景。     

高速传输系统用低损耗单模光纤的研究

介绍了国际上低损耗单模光纤的研究进展,从理论上分析了低损耗单模光纤实现的技术途径。通过对石英玻璃物理特性的研究,探索出石英玻璃光纤的退火工艺,以降低光纤的内应力从而降低光纤的衰减。采用自主知识产权的专利技术制造的光纤在1 310、1 550和1 625nm波长的衰减典型值分别为0.320、0.182和0.195dB/km。该光纤的技术指标优于ITU-T国际标准和GB/T规定的光纤指标值。     

Multichannel joint detection of multicarrier 16-QAM DS/CDMA system for high-speed data transmission

We propose a multichannel joint detector which eliminates other user, multipath, and intercarrier interference through a decorrelating process in a multicarrier 16-QAM direct-sequence code-division multiple-access system. The performance of the proposed detector under a frequency-selective fading channel is analytically derived and compared to that of a conventional single-user detector. The symbol error ratio curve of the proposed detector does not show the error floor that is seen in the conventional detector, and the resultant performance is close to that of a multicarrier 16-QAM system without any interference.     

New architecture for incoherent optical CDMA to achieve bipolarcapacity

A simple and efficient method for using bipolar codes in noncoherent optical code-division multiple access systems is proposed. The proposed system requires only incoherent optical delay lines and direct detection receivers. Practical architectures for the encoder/decoder are given. The Letter shows that combining Gold codes of period M=127 and Barker code of period K=4 into composite sequences of period N=508 allows 20 simultaneous active users for P_e=10 ^-9, while requiring only four nonprogrammable delay lines     

Layered -space-time architecture for MIMO block spread CDMA systems

In this paper, single-carrier block spread CDMA for multiple-input-multiple-output (MIMO) systems is proposed. With block spreading and despreading, multiple-user intererence free (MUI-free) transmission with reduced processing complexity is achieved. Layered space-time transmission (LST) is employed to enhance the data rak. of the proposed system. The proposed system is studied extensively under different channel conditions and its performance is compared against conventional single-carrier and multicarrier CDMA systems.     

KSA高速卫星基带数据实时处理架构设计与实现

地面终端站KSA（Ka-band Single Access）高速卫星数据传输接收系统基带数据的处理既要实现基带数据记录存储、实时转发和事后按可控制的帧频转发等业务,又要满足返向高速基带输出的处理时延不大于40 ms实时性需求。针对基带数据的处理业务多样性和实时性之间的矛盾,提出了一种基于CPCI（Compact Peripheral Component Interconnect）结构且满足基带数据的处理应用业务多样性和高实时性的处理架构,实现了一种高速卫星信号基带数据实时处理平台。经搭建测试平台并拷机500 h,该架构下的处理平台能够稳定地实时处理600 Mb/s卫星基带数据的所有业务类型,并在地面终端站KSA卫星信号数据传输系统中得到了工程实践验证。     

Output and delay process analysis for slotted CDMA wirelesscommunication networks with integrated voice/data transmission

This paper presents the output and delay process analysis of integrated voice/data slotted code division multiple access (CDMA) network systems with random access protocol for packet radio communications. The system model consists of a finite number of users, and each user can be a source of both voice traffic and data traffic. The allocation of codes to voice calls is given priority over that to data packets, while an admission control, which restricts the maximum number of codes available to voice sources, is considered for voice traffic so as not to monopolize the resource. Such codes allocated exclusively to voice calls are called voice codes. In addition, the system monitoring can distinguish between silent and talkspurt periods of voice sources, so that users with data packets can use the voice codes for transmission if the voice sources are silent. A discrete-time Markov process is used to model the system operation, and an exact analysis is presented to derive the moment generating functions of the probability distributions for packet departures of both voice and data traffic and for the data packet delay. For some cases with different numbers of voice codes, numerical results display the correlation coefficient of the voice and data packet departures and the coefficient of variation of the data packet delay as well as average performance measures, such as the throughput, the average delay of data packets, and the average blocking probability of voice calls     

Performance of antenna array transmission techniques for CDMA

The authors describe and compare techniques which estimate the reverse link channel to set up beamformer weights for antenna array transmission in a code division multiple access (CDMA) system using frequency division duplex (FDD). The results show that a single transmission is more efficient than splitting the power between multiple transmissions, but the algorithms degrade when the angle spread is wide     

基于CDMA的HFC-CATV网络双向传输

当前,光纤同轴线混合（ＨＦＣ）有线电视（ＣＡＴＶ）网络主要用于电视广播,存在大量的空闲频带资源。本文提出一种基于码分多址（ＣＤＭＡ）的使ＨＦＣ－ＣＡＴＶ网络具有双向传输能力的方案,实现ＣＤＭＡ方式的该系统能进行宽带高速传输,与ＴＤＭＡ（时分多址）比较,ＣＤＭＡ方案可以抗窄带噪声干扰。     

Optimum packet data transmission in cellular multirate CDMA systems with rate-based slot allocation

High-rate packet transmission is realized for the downlink in cellular multirate code-division multiple-access systems using multicode concatenated signaling, combined with iterative detection and self-interference cancellation. Since an optimum packet transmission is to allocate the maximum allowable rate to the user with the best received signal-to-interference-plus-noise ratio (SINR), a problem with fairness arises, in the sense that only a very small number of users receive at or near the maximum allowable rate, and the rest of the users do not receive at all. To overcome this, a new soft multimodal fairness control is proposed to adjust the latency (or waiting time) between two extreme values. Throughput is analyzed by deriving the probability distribution of the rate allocation, which is based on the maximum received SINR in a slot. For this, statistics on the SINRs are jointly characterized under three-sector cell structure because of their mutual correlation. Traffic variations are also taken into account to formulate the statistics under two algorithms for adaptive base station selection. It is shown that high-rate transmission can be achieved by a substantial reduction in in-cell interference, and the tradeoff between throughput and fairness can be met by the fairness control.