Analyzing Multi-Channel Medium Access Control Schemes With ALOHA Reservation

In order to improve the throughput performance of Medium Access Control (MAC) schemes in wireless communication networks, some researchers proposed to divide a single shared channel into several sub-channels: one as control subchannel and the others as data sub-channels. In this paper, we analyze and evaluate the maximum achievable throughput of a class of generic multi-channel MAC schemes that are based on the RTS/CTS (Ready-To-Send/Clear-To-Send) dialogue and on ALOHA contention resolution. We study these multichannel MAC schemes under two split-channel scenarios: the fixed-total-bandwidth scenario and the fixed-channel-bandwidth scenario. In the fixed-total-bandwidth scenario, we show that the throughput of the multi-channel MAC schemes is inferior to that of the corresponding single-channel MAC scheme, which sends the RTS/CTS packets and DATA packets on a single shared channel. For the fixed-channel-bandwidth scenario, where CDMA or similar techniques can be applied, we derive the optimal number of the data sub-channels that maximizes the throughput. The analytical framework that we derive in this paper can also be used to evaluate other contention resolution technique, when the average contention period is known

Analyzing multi-channel medium access control schemes with aloha reservation

Abstract — In order to improve the throughput performance of Medium Access Control (MAC) schemes in wireless communication networks, some researchers proposed to divide a single shared channel into several sub-channels: one as control subchannel and the others as data sub-channels. In this paper, we analyze and evaluate the maximum achievable throughput of a class of generic multi-channel MAC schemes that are based on the RTS/CTS (Ready-To-Send/Clear-To-Send) dialogue and on ALOHA contention resolution. We study these multichannel MAC schemes under two split-channel scenarios: the fixed-total-bandwidth scenario and the fixed-channel-bandwidth scenario. In the fixed-total-bandwidth scenario, we show that the throughput of the multi-channel MAC schemes is inferior to that of the corresponding single-channel MAC scheme, which sends the RTS/CTS packets and DATA packets on a single shared channel. For the fixed-channel-bandwidth scenario, where CDMA or similar techniques can be applied, we derive the optimal number of the data sub-channels that maximizes the throughput. The analytical framework that we derive in this paper can also be used to evaluate other contention resolution technique, when the average contention period is known. Index Terms — medium access control, MAC, shared channel, multiple channels, ALOHA, contention resolution, RTS/CTS dialogu

Can Multiple Subchannels Improve the Delay Performance of RTS/CTS-based MAC Schemes?

We analyze the delay performance of RTS/CTSbased (Request-To-Send/Clear-To-Send) multi-channel MAC (Medium Access Control) schemes for wireless networks. These schemes usually employ multiple data subchannels for data transmission and one control subchannel to send the RTS/CTS dialogue for channel reservation. Through theoretical analysis and simulations, we show that, in fully-connected networks, such multi-channel MAC schemes suffer longer delays than the corresponding single channel MAC scheme, that puts the RTS/CTS dialogue on the same channel as data packet transmissions. This conclusion holds even when data packets have different priorities and higher priority traffic is sent ahead of lower priority traffic

Analysis of the LTE Access Reservation Protocol for Real-Time Traffic

LTE is increasingly seen as a system for serving real-time Machine-to-Machine (M2M) communication needs. The asynchronous M2M user access in LTE is obtained through a two-phase access reservation protocol (contention and data phase). Existing analysis related to these protocols is based on the following assumptions: (1) there are sufficient resources in the data phase for all detected contention tokens, and (2) the base station is able to detect collisions, i.e., tokens activated by multiple users. These assumptions are not always applicable to LTE - specifically, (1) due to the variable amount of available data resources caused by variable load, and (2) detection of collisions in contention phase may not be possible. All of this affects transmission of real-time M2M traffic, where data packets have to be sent within a deadline and may have only one contention opportunity. We analyze the features of the two-phase LTE reservation protocol and derive its throughput, i.e., the number of successful transmissions in the data phase, when assumptions (1) and (2) do not hold.Comment: 4 Pages, 4 Figures, Accepted in IEEE Communication Letters on the 20th of May 201

Analyses of MAC Performance for Multi-Carrier based Wireless Sensor Networks

In this work we adopt an OFDMA like Multi-Carrier scheme for wireless sensor networks with the aim of improving the performance in the presence of intensive traffic load. To examine the MAC performance, a simple, yet accurate analytic model has been provided, validated by simulation results. We demonstrate that the proposed scheme can achieve better throughput under heavy offered traffic load, as a result of the higher bandwidth utilisation. In addition, energy efficiency and service delay performance can be significantly increased as well in this architecture

A Reservation Protocol Analysis for Multi-Channel Wireless Networks

A synchronous multi-channel multi-access Medium Access Control (MAC) protocol for Wireless Local Area Networks (WLANs) is studied in this paper. The proposed protocol introduces an access control reservation scheme and requires a single radio per station. The receiver collisions phenomenon characterizes the performance of the proposed multi-channel system. A priority scheme is considered in order to primary serve the time-sensitive traffic such as voice, as compared to the delay tolerant data traffic. The innovation of this paper is the extensive and accurate study of the receiver collisions effect on the network performance in multi-traffic environment. An analytic discrete time Markovian model is developed for finite number of stations and channels. The performance measures of throughput, delay, and average rejection probability at destination are analytically estimated. Numerical results are presented for comparison for various numbers of channels and stations. The proposed MAC protocol provides a substantial contribution to the understanding of wireless multi-channel multi-traffic environments

Evaluating Opportunistic Multi-Channel MAC: Is Diversity Gain Worth the Pain?

We evaluate the performance of an opportunistic multi-channel medium access control protocol and compare it to that of the corresponding single-channel MAC (S-MAC) and a non-opportunistic multi-channel MAC (M-MAC). We do this in three different settings: (1) an ideal scenario where no control channel is used and no sensing delay is incurred, (2) a more realistic scheme where users compete for access on a control channel using random access, and (3) a scheme similar to (2) but with a time-division multiplexing (TDM) based access scheme on the control channel. Our analysis and numerical results show that in terms of delay performance, the random access and competition on the control channel, which typically occupy a fraction of the total bandwidth, almost always wipe out the channel diversity gain, a main motivation behind an opportunistic multichannel MAC. On the other hand opportunistic access increases bandwidth utilization which reduces the system’s total busy time. As a result it helps reduce power consumption in general. When TDM is employed on the control channel, the data sub-channel sensing delay becomes the main bottleneck to attaining better performance. In this case the performance of opportunistic multichannel MAC gets closer to that of the single-channel MAC when the channel sensing overhead is substantially reduced

Implementation and Application of Multiple-Access Technique Based on SDMA

为解决信号全向发射带来的电磁污染和相互干扰问题,提出了一种全新的多址接入方式——智能天线系统。在多址技术的基础上,引入了空分多址系统模型,并对空分多址系统实现方案进行了较详细而全面地分析。同时,对空分多址方式与传统多址方式结合应用进行分析。计算机模拟结果表明了仿真与理论的一致性。To solve the signal the whole bring to the emission of electromagnetic pollution and interfere with each other,a new multiple access smart antenna systems.On the basis of the multiple access technology,the introduction of the SDMA(space-division multiple access) system model,and space division multiple access system to carry out a more detailed and comprehensive analysis.The SDMA combined with the traditional multiple access,analyze the application.The computer simulation results show that the simulation and theoretical consistency.国家自然科学基金资助项目(60362001;69862001