Uplink PID power control technique for TDMA‐based cellular radio systems

The efficient management of wireless resource is essential to the success of wireless systems. While power control is traditionally considered to be a means to counteract the detrimental effects of channel fading, it is also a flexible mechanism that achieves high link quality, high bandwidth utilization, and low power consumption, which are mainly driven in cellular radio systems. Once the power control algorithm provides a lower outage probability, the SUs experienced adequate link quality need not to competitively increase their transmission power. Spontaneously, the systems with lower power consumption and better bandwidth efficiency are achieved. In this paper, a novel power control based on the proportional‐integration‐derivative (PID) controller is proposed, and its performance with an autonomous closed‐loop uplink power control model under the time division multiple access (TDMA) systems is presented. Computer simulation is used to illustrate the performance of the proposed power control algorithm in a cellular radio system with Rayleigh fading channels. The results show that our proposed power control algorithm is remarkably superior to several previous power control methods, especially in a short power control period. Copyright © 2006 John Wiley & Sons, Ltd.     

Linear and non‐linear space diversity combining algorithms over fading channels in TDMA systems

This paper investigates the performances of various adaptive algorithms for space diversity combining in time division multiple access (TDMA) digital cellular mobile radio systems. Two linear adaptive algorithms are investigated, the least mean square (LMS) and the square root Kalman (SRK) algorithm. These algorithms are based on the minimization of the mean‐square error. However, the optimal performance can only be obtained using algorithms satisfying the minimum bit error rate (BER) criterion. This criterion can be satisfied using non‐linear signal processing techniques such as artificial neural networks. An artificial neural network combiner model is developed, based on the recurrent neural network (RNN) structure, trained using the real‐time recurrent learning (RTRL) algorithm. It is shown that, for channels characterized by Rician fading, the artificial neural network combiners based on the RNN structure are able to provide significant improvements in the BER performance in comparison with the linear techniques. In particular, improvements are evident in time‐varying channels dominated by inter‐symbol interference. Copyright © 2001 John Wiley & Sons, Ltd.     

An Alternative Queuing Technique to Optimize the Performance of TDMA Based Mobile Communication Systems

This paper analyses an alternative traffic queuing model for the quality of service (QoS) optimization in mobile communications systems. According to the proposed model, the queue of handover attempts is separated to each of the used transceivers of a base transceiver station that covers a particular area. Fixed channel assignment and TDMA are considered, while the proposed technique is compared to the classic queuing model. The comparison results show that the QoS of the proposed model is fully optimized, especially if large queue sizes are chosen.     

改进的紫外光通信网络TDMA邻居发现算法

针对节点数较多的紫外光固定拓扑网络,设计了一种基于时分多址接入(Time Division mMultiple Access,TDMA)技术的紫外光帧结构,结合紫外光大气传输特性提出了一种紫外光定向邻居发现算法.仿真对比了该算法和传统算法的性能,并对该算法不同退避延时下的节点发现效率进行了理论分析和仿真验证.     

Performance evaluation of a satellite-switched variable-frame TDMA system

In satellite-switched time-division multiple access (SS/TDMA) systems, the demand assignment control is a suitable scheme for the bursty packets to enhance the capacity efficiency. In the system, by applying the demand assignment scheme, the minimum transmission time could be achieved by the efficient time slot assignment algorithm. According to a given traffic matrix, the minimum transmission time cannot exceed the fixed TDMA frame duration. The spare time may be left at the end of the TDMA frame as the growth space for the future needs. To increase the system efficiency, the spare time could be reduced. In this paper, a demand assignment protocol with a variable frame is proposed for the system. The Markov chain model is applied to analyze the system performance on throughput, balking probability and packet delay. Performance comparison with the previous presented protocol, the proposed protocol could show a simple control technique and the efficient performance results in the system. It is a suitable candidate to be employed in the satellite networks to provide communication between the satellite and earth stations.     

Adaptive rate control algorithm for low power video coding systems

With the recent development of third-generation communication technologies, low power video coding system (such as PDA, Handphone or system on chip) has found wide applications such as live video using a PDA and sharing it among friends, etc. However, video coding in a low power system has two major hurdles to overcome: (1) In a low power system, video coding needs to meet the rigorous constraints of the available memory and computational capacity; (2) In a low power system, the computational power allocated to video coding may vary drastically (in bursts). In this paper, a new adaptive rate control algorithm is proposed for low power video coding system. This adaptive rate control scheme takes into account the time constraint of a low power system, and its bit allocation depends not only on the available data bits, but more importantly, on the available coding time. Experimental results show that, compared to the existing rate control scheme, the new algorithm can always achieve the maximum frame rate, maximize the utilization of the available bandwidth and computing power, increase the average PSNR, and improve the subjective perceptual quality of the reconstructed video.     

话音/数据综合的多时隙预约多址协议及其性能分析

本文提出了一种综合话音和数据的多时隙预约多址协议.该协议在保证话音终端的优先权的情况下,允许数据终端在报文的传输期间在连续多个帧中预约多个信息时隙.文中对协议进行了理论分析,并推导出了协议的重要性能指标(如话音分组丢失率、数据报文平均接入时延、系统平均吞吐率等)的解析表达式.研究表明,该协议可以支持比IPRMA、NC-IPRMA更高的等效数据终端速率,而且系统平均吞吐率在很大的负载范围内接近最大值.     

一种新的紫外光自组织网络的时分多址接入邻居发现算法

为了适应大 规模及拓扑变化较快的紫外光(UV)自组织网络,本文以提高邻居发现概率为目的,提出了一 种基于时分多址接入(TDMA, time division multiple access)的UV定向邻居发现新算法。新算法在DTRA(directional transmission and reception algorithm)协议的基础上采用了退避时延机制, 并通过邻居判断和维护机制让节点快速更新本地邻居表。实验结果表明,新 算法充分考虑了UV大气传输特性,能够有效地解决节点冲突问题,并通过找到一个最佳退避 时延使得节点冲突 概率和邻居发现时延之间达到一个较好的平衡。     

Design of a selective FEC subsystem to counteract rain fading in ku-band TDMA systems

A major concern in satellite communications systems operating at frequencies above 10 GHz (e.g. Ku band) is the performance degradation caused by rain fading. In this paper, an effective method for combatting this phenomenon in TDMA systems is described. This method is based on the application of additional FEC coding protection on a dynamic basis to faded traffic terminals. Selective (adaptive) forward error correction (S-FEC) coding permits the fixed fade margins used by the network earth-stations to be substantially reduced, while a desired outage probability is maintained. This paper deals primarily with the implementation of the monitoring and control subsystems required in a practical S-FEC network.     

运动TDMA系统目标时差定位算法

根据时分多址(TDMA)系统的同步特征,利用TDMA运动目标准周期性信号的到达时间,提出了3种在三站时差定位系统中实现目标定位的算法.采用目标运动分析的方法,对TDMA目标位置的可观测性进行分析,提出了目标运动分析时差定位算法,利用目标航迹上多个位置的时差实现目标的定位.运用目标运动分析测距算法,提出了测距与传统时差定...     

Performance of slow-frequency-hopped TDMA with a hard-limited receiver

In recent years, various access technologies have been studied for wireless access to telephone networks and for personal digital radio communications. This paper discusses the performance of a slow-frequency-hopped time-division multiple access (SFH-TDMA) technique, which can be considered as a high-tier extension of a low-complexity TDMA architecture optimized for low-power pedestrian applications. A hard-limited receiver is employed, and a novel weighting factor for diversity combining is developed to achieve an effect similar to that of a maximal ratio combiner. Numerical performance results for frequency-selective and non-frequency-selective fading channels over a range of fading rates were obtained through computer simulations. Results indicate that, with the proposed weighting factor for diversity combining, the degradation due to receiver hard-limiting is less than 1.5 dB in a SFH-TDMA system.     

The TDMA burst-mode link analyser with least-squares algorithm

The burst-mode link analyser with the decompositional least-squares algorithm (BMLA/LS) is an attractive and novel computational approach for impulse response measurement and equalization of a QPSK/TDMA satellite communication channel. Analysis and simulation confirms it to be superior to the current BMLA/radar approach. This paper presents a brief and systematic introduction to the methodology of the subject, and to software simulation, system design and hardware implementation.     

VANET中基于协议序列及TDMA的混合信道接入机制

为了提高高速公路场景下用户平均有效数据吞吐量,提出车载自组织网络分布式信道接入机制.通过道路区段划分实现协议序列集复用;通过引入少量反馈并利用UI(User Irrepressibility)序列特性实现节点间接入顺序感知;同区段节点间利用分布式TDMA(Time Division Multiple Access)模式最大化吞吐量.仿真结果表明,其吞吐量性能优于经典的基于GNSS(Global Navigation Satellite Systems)的机制,并且物理层数据传输速率越大,节点通信半径越大,车辆密度越稀疏,其优势越明显.     

Queue length aware power control for delay‐ constrained communication over fading channels

In this paper, we study efficient power control schemes for delay sensitive communication over fading channels. Our objective is to find a power control law that optimizes the link layer performance, specifically, minimizes the packet drop probability, subject to a long‐term average power constraint. We assume the buffer at the transmitter is finite; hence packet drop happens when the buffer is full. The fading channel under our study has a continuous state, e.g., Rayleigh fading. Since the channel state space is continuous, dynamic programming is not applicable for power control. In this paper, we propose a sub‐optimal power control law based on a parametric approach. The proposed power control scheme tries to minimize the packet drop probability by considering the queue length, i.e., reducing the probability of those queue‐length states that will cause full buffer. Simulation results show that our proposed power control scheme reduces the packet drop probability by one or two orders of magnitude, compared to the time domain water filling (TDWF) and the truncated channel inversion (TCI) power control. Copyright © 2010 John Wiley & Sons, Ltd.     

宽带CDMA系统的自适应功率和速率控制性能分析

该文研究一种新的自适应功率和速率控制方案,导出了采用这种方案的宽带CDMA系统的误比特率(BER)公式,并分别给出了系统在平坦衰落信道和多径衰落信道中性能分析的数值结果。在这种方案中,移动台根据衰落信道的变化自适应地调整其发射功率和传输速率,而衰落信道的变化通过一种新的远程预测算法进行预测。首先将预测的总平均信道功率的概率密度函数划分为若干个面积相同的区间,从而得出这些区间之间的门限值;然后通过与传统功率控制技术相似的方式,将这些门限值用于自适应功率和速率控制。数值结果表明,采用这种方案能够有效地提高宽带CDMA系统的理论BER性能。     

An energy-efficient power allocation scheme for millimeter-wave MIMO-NOMA systems

There are many challenges in fifth generation (5G) telecommunication systems, due to the increasing demands and applications. The most important of which are need to have higher energy efficiency (EE) and spectral efficiency (SE). They are critical in the practical multiple-input multiple-output (MIMO) telecommunication systems. Non-orthogonal multiple access (NOMA) methods and millimeter-waves can be used in conjunction with MIMO systems to improve their EE and SE performance. In this paper, we investigate the application of NOMA and mm-Wave transmission in the downlink of MIMO systems. Then, we formulate the optimization problem for users in MIMO-NOMA systems to maximize the EE that is subject to minimum data rate to satisfy required quality of service (QoS) and maximum transmission power. To achieve the optimal power allocation for users, we reach a problem for the EE maximization that is non-convex and solution of the optimization problem is not trivial. We exploit a lower bound of the data rate and the Lagrange dual function to convert it to a convex and unconstrained problem, which is easy to solve. In the next step, we derive a relation for determining the optimal power allocation of users. In addition, a numerical algorithm is presented that can be used to solve the problem. According to the simulation results of the proposed algorithm, our method performs better and provides higher EE than both orthogonal multiple access and equal power allocation schemes.     

FDD无线通信系统闭环功率控制发射波束跟踪算法

提出了一种适用于FDD无线通信系统的变步长智能天线下行发射波束跟踪算法.该算法利用闭环功率控制的反馈信息,可自适应地跟踪移动台方位角的变化.算法不需要专门的探测信号,不需要求解信道协方差矩阵,复杂度很低.还分析了功率控制步长对用户方位角跟踪误差的影响.与其它方法相比,新方法具有更小的跟踪误差及更快的收敛速度.     

Forward link partial-balance power control algorithm for W-CDMA communication

Balance power control is based on the idea of balancing Carrier to Interference Ratio (CIR) of all wireless links. Unbalance power control means that different traffics can achieve different CIR at receivers. This paper proposes a forward link partial-balance power control algorithm, which can provide necessary Quality of Service (QoS) for multimedia traffics in Wideband CDMA(W-CDMA) systems. The proposed algorithm is the integration of grading traffics priority and allocating and adjusting forward link power levels. For higher priority traffics, the unbalance power control is used. Whereas for lower priority traffics, balance power control is adopted. Computer simulation results show that the proposed algorithm can guarantee the special QoS requirements of the traffics with higher priority orders and maximize the CIR of the traffics with lower priority orders.     

多业务CDMA蜂窝移动通信系统的功率控制

本文提出了多业务CDMA蜂窝移动通信系统的一种下行链路功率控制策略，系统的最优功率分配可以归结为求解归一化链路增益矩阵在有约束条件下的最大实特征值。在对系统的最优功率分配进行理论分析的基础上，给予了相应的仿真结果，并针对实际系统负载过重的情形，提出了按照业务优先级别逐步去除小区用户的功率控制策略。     

S-CDMA-HFC系统初始接入改进功率控制算法

功率控制是S-CDMA-HFC系统上行信道的关键技术之一。对于初始接入CDMA终端,采用传统的功率控制方法是不合理的。该文提出了一种初始接入改进功率控制算法,给出了吞吐量和接入时延性能仿真结果,并与传统功率控制算法的性能进行了比较。