European Transactions on Telecommunications最新文献

{"title":"Spectral and power efficiency trade-offs for multiple-antenna reception techniques under co-channel interference","authors":"Ö. Ertug","doi":"10.1002/ett.1535","DOIUrl":"https://doi.org/10.1002/ett.1535","url":null,"abstract":"Spatial receive diversity and beamforming are two competing multiple-antenna reception strategies for enhancement of spectral and power efficiency of wireless communication systems because they both use the same resource, that is the spatial degrees of freedom. We analyse in this paper ergodic, block-fading outage and delay-limited outage spectral efficiencies as well as average bit error rates and service outage probabilities of a hybrid diversity-beamforming receiver with antenna partitioning over flat Rayleigh-fading uplink channels under co-channel interference. The results validated by Monte Carlo simulations decipher the trade-offs in terms of spectral and power efficiencies in between all-diversity, hybrid diversity-beamforming and all-beamforming reception for different scenarios represented by average signal-tonoise ratio per path and desired signal-to-interference ratio for using these multiple-antenna reception techniques in interference-limited wireless communication systems. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"139 1","pages":"415-427"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86554609","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}

{"title":"Interaction of multiplexing gains and power exponents allocation of two-level superposition coding relaying","authors":"Xiangdong Jia, Longxiang Yang","doi":"10.1002/ett.1486","DOIUrl":"https://doi.org/10.1002/ett.1486","url":null,"abstract":"A two-level rate superposition coding relaying (SC-relaying) scheme is discussed, in which only the relay-to-source channel state information feedback (CSF) is considered and, at source, a long power constraint is imposed on the basic signal S0 and the additional signal S1 whose multiplexing gains are r0 and r1, respectively. The CSF index is constructed based on the correct decoding of the signal S0 at relay. For the SC-relaying scheme, we propose a multilevel iteration constructing rule for the CSF index. With the proposed CSF constructing rule, the allocation method of the power signal-to-noise ratio exponents is first obtained by the investigation of the optimal outage exponent of the signal S0. Secondly, we obtain the value range of p11, p11  ∈ [1,1∕r0], by studying the outage exponent lower bound of the signal S0, where p11 denotes the minimum of the power signal-to-noise ratio exponent of the signal S. Lastly, to observe the interaction between the multiplexing gains r0 and r1, we discuss the closed-form solution of the lower bound of the optimal outage exponent for the signal S1, through which we find that the multiplexing gain constraint is r1  ≤ 1 −r0p11, p11  ≥ 1. The substantial numerical analyses show that the results in this paper are reasonable. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"23 1","pages":"352-366"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82710932","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}

{"title":"Fast decoding of the (23, 12, 7) Golay code with four-error-correcting capability","authors":"Shao-I Chu, Hung-Peng Lee, Hsin-Chiu Chang","doi":"10.1002/ett.1491","DOIUrl":"https://doi.org/10.1002/ett.1491","url":null,"abstract":"In this paper, a fast and efficient decoding algorithm for correcting the (23, 12, 7) Golay code up to four errors is presented. The aim of this paper is to develop a fast syndrome-group search method for finding the candidate codewords by utilizing the property that the syndromes of the weight-4 error patterns are identical to that of the weight-3 error pattern. When the set of the candidate codewords is constructed, the most likely one is determined by assessing the corresponding correlation metrics. The well-known Chase-II decoder, which needs to perform the hard-decision decoder multiple times, acts as a comparison basis. Simulation results over the additive white Gaussian noise channel show that the decoding complexity of the proposed method is averagely reduced by at least 86% in terms of the decoding time. Furthermore, the successful decoding percentage of the new decoder in the case of four errors is always superior to Chase-II decoder. At the signal-to-noise ratio of 0 dB, the proposed algorithm still can correct up to 97.40% weight-4 error patterns. The overall bit error rate performance of the proposed decoder is close to that of Chase-II decoder. It implies that the new decoder is beneficial to the practical implementation. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"22 1","pages":"388-395"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75561105","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}

{"title":"Joint channel-network coding strategies for networks with low-complexity relays","authors":"Sarah J. Johnson, L. Ong, C. Kellett","doi":"10.1002/ett.1492","DOIUrl":"https://doi.org/10.1002/ett.1492","url":null,"abstract":"We investigate joint network and channel coding schemes for networks when relay nodes are not capable of performing channel coding operations. Rather, channel encoding is performed at the source node, whereas channel decoding is carried out only at the destination nodes. We examine three different decoding strategies: independent network-then-channel decoding, serial network and channel decoding, and joint network and channel decoding. Furthermore, we describe how to implement such joint network and channel decoding using iteratively decodable error correction codes. Using simple networks as a model, we derive achievable rate regions and use simulations to demonstrate the effectiveness of the three decoders. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"69 1","pages":"396-406"},"PeriodicalIF":0.0,"publicationDate":"2011-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90936650","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}

{"title":"The uplink coverage-capacity trade-off in CDMA-based multihop cellular networks","authors":"Z. Dawy","doi":"10.1002/ett.1512","DOIUrl":"https://doi.org/10.1002/ett.1512","url":null,"abstract":"We propose a novel design for incorporating multihop transmission in code division multiple access-based cellular systems to notably reduce the intercell interference in the network. Different design issues are considered such as the allowed number of hops, type of relay stations, relay selection, accessing scheme and duplexing mode. Numerical derivations demonstrate that the intercell interference can be significantly reduced. Moreover, a link budget analysis is performed to obtain coverage-capacity trade-off results. It is shown that with single user detection receivers at base stations, gains up to 100% in area coverage are achieved with moderate to low user loads. Furthermore, by deploying advanced interference cancellation receivers at base stations to combat intracell interference, the proposed multihop-based design achieves very high gains in pole capacity and area coverage per cell. Additionally, practical implementation issues are addressed, and results are compared between omni-directional and three-sector network structures. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"25 1","pages":"522-533"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82556928","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}

{"title":"WCDMA multiservice uplink capacity of highways cigar-shaped microcells with adjacent channel interference","authors":"B. Ahmed, M. Calvo-Ramón","doi":"10.1002/ett.1483","DOIUrl":"https://doi.org/10.1002/ett.1483","url":null,"abstract":"The multiservice uplink capacity and the interference (intracellular and intercellular) statistics (mean and variance) of the sectors of the cigar-shaped wide band code division multiple access microcell are studied, taking into account the impact of the adjacent channel interference. A model of five microcells (10 sectors) is used in the analysis. The two-slope propagation loss model with lognormal shadowing is used in the analysis. The capacity and the interference statistics of the microcell are studied for different values of the distance between the base station of the two systems (system under study and the system using the adjacent channel). It is noted that for a distance between the base stations of both systems of 100 m, the capacity reduction due to the adjacent channel interference is lower than 3.4% (for data service). For collocated systems, capacity reduction is negligible. It is noticed that increasing the adjacent channel leakage power ratio from 30 to 40 dB will increase the sector uplink capacity by only 3%. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"19 1","pages":"322-331"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82796386","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}

{"title":"Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays","authors":"Lei You, Ping Wu, Mei Song, Junde Song, Yong Zhang","doi":"10.1002/ett.1480","DOIUrl":"https://doi.org/10.1002/ett.1480","url":null,"abstract":"In this paper, we consider a cross-layer design aimed to enhance performance for uplink transmission in an orthogonal frequency division multiple-access (OFDMA)-based cellular network with fixed relay stations. Because mobile stations (MSs) spend most of the power on the uplink transmission, power efficiency resource allocation becomes very important to MSs. We develop a cross-layer optimisation framework for two types of uplink flows (inelastic and elastic flows) that have different quality-of-service requirements. For inelastic flows with fixed-rate requirement, we formulate the cross-layer optimisation problem as the minimisation of the sum transmission power of MSs under the constraints of flow conservation law, subcarrier assignment, relaying path selection and power allocation. For elastic flows with flexible-service-rate requirement, we consider the cross-layer trade-off between uplink service rate and power consumption of MSs and pose the optimisation problem as the maximisation of a linear combination of utility (of service rates) and power consumption (of MSs). Different trade-offs can be achieved by varying the weighting parameters. Dual decomposition and subgradient methods are used to solve the problems optimally with reduced computational complexity. The simulation results show that, through the proposed cross-layer resource optimisation framework and algorithms, significant benefits of deployment of multiple fixed relays in an OFDMA cellular network can be fully obtained such as reduction in power consumption, increase in service rate and energy savings in the uplink transmission of MSs. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"18 1","pages":"296-314"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86620415","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}

{"title":"An analytic model for enhancing IEEE 802.11 point coordination function media access control protocol","authors":"Qianlin Liu, Dongfeng Zhao, Dongming Zhou","doi":"10.1002/ett.1482","DOIUrl":"https://doi.org/10.1002/ett.1482","url":null,"abstract":"The design of media access control (MAC) protocol that can efficiently support the real-time applications in Wireless Local Area Networks (WLANs) is a challenging task, it requires that the MAC layer provide strict delay guarantees for sensitive traffic, the Point Coordination Function (PCF) with Round Robin (RR) polling scheme has been included in IEEE 802.11 MAC protocol to achieve this objective. However, the RR scheme seems difficult to guarantee QoS and satisfy the low delay of the sensitive traffic, yet it can hardly differentiate from priority service for the key station. Thus we utilize an analytic model with two-level-polling mechanism to enhance the RR scheme, and the comparison results show us that the efficiency as well as impartiality of proposed scheme is better than that of the RR scheme. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"45 1","pages":"332-338"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74148235","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}

{"title":"Reciprocity for MIMO systems","authors":"C. Withers, S. Nadarajah","doi":"10.1002/ett.1476","DOIUrl":"https://doi.org/10.1002/ett.1476","url":null,"abstract":"We give reciprocity results for the channel capacity efficiency (i.e. the capacity/bandwidth – abbreviated here to capacity) of an N-transmit M-receive antenna wireless system, when the gain matrix is known to the receiver but not the transmitter. The channel may be non-Gaussian. Transmitter power or receiver noise may be variable. We consider the case when N or M is large but not both. \u0000 \u0000 \u0000 \u0000Formulas are also given for the mean capacity when there is correlation at both ends. Capacity is approximately Gaussian. For a non-Gaussian channel the approximate mean capacity is not changed but the variance is increased by a certain factor. It is noted that reciprocity fails. The key to making it work is to introduce a ‘power factor’ that allows for the case when the power of each transmitter does not depend on N as well as for the usual case when the total power is fixed. Copyright © 2011 John Wiley & Sons, Ltd.","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"2 1","pages":"276-281"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85141107","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}

{"title":"Influence of imperfect cophasing on performance of EGC receiver of BPSK and QPSK signals transmitted over Weibull fading channel","authors":"G. Djordjevic, Dejan N. Milic, A. Cvetkovic, M. Stefanovic","doi":"10.1002/ett.1475","DOIUrl":"https://doi.org/10.1002/ett.1475","url":null,"abstract":"This paper presents an analysis of maximum ratio combining (MRC) receiver of quaternary phase-shift keying (QPSK) signals transmitted over a Weibull fading channel. We determine the influence of imperfect cophasing and branches unbalance on bit error rate dependence on average signal-to-noise ratio. The performance dependence on diversity order and fading severity is also observed. Keywords — Cophasing, Diversity systems, Error probability, Fading. I. INTRODUCTION N order to reduce the influence of multipath fading on signal detection, it is possible to use spatially separated receiver antennas at the reception and to combine the signals from different branches of the receiver in a certain manner. The optimal combining technique is maximum ratio combining (MRC). This combining technique involves cophasing of the useful signal in all branches, multiplication of the received signal in each branch by the estimated envelope of that particular signal and summing of the received signals from all antennas (1). By cophasing, all the random phase fluctuations of the signal that emerged during the transmission are eliminated. For this process it is necessary to estimate the phase of the received signal. This phase estimation can be performed from the modulated or unmodulated received signal carrier. In previous papers concerning this matter the assumptions of the ideal phase estimation of the incoming signal were mainly used (2), (3). Only in (4) and (5) the influence of the imperfect phase estimation was examined and that was in the case of the equal gain combining (EGC) in the receiver. In paper (4), the influence of the phase error on the error probability in the case of digital binary (BPSK) and quaternary phase-shift keying (QPSK) signal detection was observed. This error probability was calculated applying the Gram-Charlier expansion. The analysis is performed under the assumption of the uncorrelated Rayleigh fading at receiving antennas. In paper (5) closed-form expressions for outage probability and error probability during the BPSK and QPSK signal detection over the Nakagami-m fading channel were obtained. Dual branch EGC technique was applied. In both papers the analysis of the system was done under the assumption that the branches of the receiver are balanced. However, as it is well-known (6), it is very rare to meet in practice the identical propagation paths in each branch. Also, the electrical components in different branches of the receiver are not ideal. Thus, it is also of interest to consider the influence of the branch unbalance in the receiver on system performances. In this paper an analysis of QPSK signal reception is presented. The signal is transmitted over the Weibull fading channel and MRC technique is applied in the receiver, while the receiving branches are assumed unbalanced. The phase estimation is performed from the unmodulated carrier and is not ideal. The difference between the phase of the incoming signal and the estimated","PeriodicalId":50473,"journal":{"name":"European Transactions on Telecommunications","volume":"52 1","pages":"268-275"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82743751","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}