2009 6th International Symposium on Wireless Communication Systems最新文献_第10页

A novel spectrum sensing method using multi-antennas without channel state information 一种新的无信道状态信息的多天线频谱感知方法

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285330

A. Al-Abbasi, T. Fujii

引用次数: 3

Empirical analysis of UMTS propagation channel (2127.6 MHz) for case of stationary receiver 固定接收机情况下UMTS传播信道(2127.6 MHz)的实证分析

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285239

Irena Janković, A. Neskovic, N. Neskovic, G. Paunovic

引用次数: 1

A continuous-space analytical approach for relay node placement in hybrid cellular and ad hoc networks 混合蜂窝和自组织网络中中继节点放置的连续空间分析方法

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285305

Z. Abbas, F. Li

引用次数: 0

On the effectiveness of IEEE 802.11e implementations in real hardware IEEE 802.11e实现在实际硬件中的有效性

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285291

R. Bolla, R. Rapuzzi, M. Repetto

{"title":"On the effectiveness of IEEE 802.11e implementations in real hardware","authors":"R. Bolla, R. Rapuzzi, M. Repetto","doi":"10.1109/ISWCS.2009.5285291","DOIUrl":"https://doi.org/10.1109/ISWCS.2009.5285291","url":null,"abstract":"Real-time multimedia traffic requires some minimum delivery guarantees to be effectively transmitted over packet-switched networks. This is even more necessary when interactive sessions (e.g., Voice-over-IP applications) are involved. Effective and timely packet delivery is sometimes achieved by overdimensioning network capacity. However, this is not the most practical and economic solution. Instead, providing a specific service to different traffic types may achieve better results without wasting network resources. Quality of Service (QoS) be implemented at different layers of the protocol stack, but tight control at the link layer is essential when the physical medium is shared among a number of devices. Wireless LANs are a typical example of that. The IEEE 802.11e amendment enhances the original version of the WiFi standard with new QoS functionalities. It maintains backward compatibility with legacy hardware, and this may cause the priority scheme to be ineffective in those deployments where non-QoS enabled hardware is present. In this paper, we analyze some widespread commercial 802.11 products to check the effectiveness of the QoS mechanisms. We show that all hardware under examination fails in providing effective QoS guarantees when legacy stations are present.","PeriodicalId":344018,"journal":{"name":"2009 6th International Symposium on Wireless Communication Systems","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122879889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Vehicle-roadside-vehicle relay communication network employing multiple frequencies and routing function 采用多频率和路由功能的车路车中继通信网络

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285301

Y. Yamao, Kazuya Minato

引用次数: 26

Tag movement direction estimation methods in an RFID gate system RFID门系统中标签运动方向估计方法

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285228

Y. Oikawa

引用次数: 12

An efficient decoding algorithm for tailbiting codes on wireless channels 一种有效的无线信道尾咬码译码算法

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285310

J. Ortín, P. G. Ducar, F. Gutiérrez, A. Valdovinos

{"title":"An efficient decoding algorithm for tailbiting codes on wireless channels","authors":"J. Ortín, P. G. Ducar, F. Gutiérrez, A. Valdovinos","doi":"10.1109/ISWCS.2009.5285310","DOIUrl":"https://doi.org/10.1109/ISWCS.2009.5285310","url":null,"abstract":"Tailbiting convolutional codes will be used for several applications in new cellular mobile radio systems. This encoding method does not reset the encoder memory at the end of each data block, avoiding the overhead of the zero tail and improving the efficiency, especially when encoding short data blocks. Nevertheless, the absence of a known tail highly increases the complexity of the decoding process. This fact added to the heavy computational burden of maximum likelihood (ML) decoding have made necessary the development of decoding algorithms which achieve good performance in terms of computational complexity and error correction capabilities. In this work we propose a novel decoding algorithm for tailbiting codes which is suitable for wireless environments with steep variations in channel conditions. The proposed method performs two different Viterbi decodings of the received data. In the first one, the most likely state is estimated with a modified version of the soft-output Viterbi algorithm (SOVA). The second one consists of a conventional Viterbi decoding which employs the state estimated in the previous step as the initial and final states of the trellis. Simulations results obtained in an orthogonal frequency division multiplexing (OFDM) system over a wireless channel are close to the performance of the maximum-likelihood decoding and other proposed algorithms.","PeriodicalId":344018,"journal":{"name":"2009 6th International Symposium on Wireless Communication Systems","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134030303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Error rate of low duty DS-IR over selective channels 低占空DS-IR在选择性信道上的错误率

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285343

L. Piazzo

引用次数: 1

Look-Ahead Sphere Decoding: Algorithm and performance evaluation 前瞻球体解码:算法与性能评估

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285361

M. Gamba, G. Masera

引用次数: 0

Symbol MAP detection aided with first channel estimate for TDMA systems over a frequency selective channel 在频率选择信道上辅助TDMA系统第一信道估计的符号MAP检测

2009 6th International Symposium on Wireless Communication Systems Pub Date : 2009-09-07 DOI: 10.1109/ISWCS.2009.5285261

I. Kammoun, M. Siala, N. Sellami, A. Roumy

{"title":"Symbol MAP detection aided with first channel estimate for TDMA systems over a frequency selective channel","authors":"I. Kammoun, M. Siala, N. Sellami, A. Roumy","doi":"10.1109/ISWCS.2009.5285261","DOIUrl":"https://doi.org/10.1109/ISWCS.2009.5285261","url":null,"abstract":"In this paper, we consider joint iterative equalization and channel estimation for TDMA systems over a frequency selective, quasi-static fading channel. We assume a slowly varying channel impulse response from one burst to the following one. We modify the maximum a posteriori (MAP) criterion by taking into account an a priori channel estimate obtained from the burst preceding the one processed. Assuming that the receiver knows the channel statistics, we propose to use the EM (Expectation-Maximization) algorithm for a joint iterative equalization and channel estimation. During each iteration of the receiver, the EM algorithm reestimates the channel by using the a posteriori probabilities (APP) available at the output of the equalizer. The algorithm we propose has linear-time complexity per iteration. Simulations show that our MAP receiver reaches the performance of the MAP equalizer with perfect channel knowledge after a few iterations, for high SNR and for small values of normalized Doppler spread. They show also that our receiver outperforms the MAP equalizer that uses a channel estimate obtained by using a training sequence.","PeriodicalId":344018,"journal":{"name":"2009 6th International Symposium on Wireless Communication Systems","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130534979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1