IET Communications
Volume 11, Issue 2, 26 January 2017
Volumes & issues:
Volume 11, Issue 2
26 January 2017
-
- Author(s): Hongyan Cui ; Yang Li ; Xiaofei Liu ; Nirwan Ansari ; Yunjie Liu
- Source: IET Communications, Volume 11, Issue 2, p. 161 –167
- DOI: 10.1049/iet-com.2016.0417
- Type: Article
- + Show details - Hide details
-
p.
161
–167
(7)
Cloud computing enables service sharing in a massive scale via network access to a pool of configurable computing resources. It has to allocate resources adaptively for tasks and applications to be executed effectively and reliably in a large scale, highly heterogeneous environment. Resource allocation in cloud computing is an NP-hard problem. In this study, the authors conduct a reliability analysis of cloud services by applying a Markov-based method. They formulate the cloud scheduling problem as a multi-objective optimisation problem with constraints in terms of reliability, makespan, and flowtime. Furthermore, they propose a genetic algorithm-based chaotic ant swarm (GA-CAS) algorithm, in which four operators and natural selection are applied, to solve this constrained multi-objective optimisation problem. Simulation results have demonstrated that GA-CAS generally speeds up convergence and outperforms other meta-heuristic approaches.
- Author(s): Zihao You and I-Tai Lu
- Source: IET Communications, Volume 11, Issue 2, p. 168 –176
- DOI: 10.1049/iet-com.2015.1227
- Type: Article
- + Show details - Hide details
-
p.
168
–176
(9)
This study presents an unsaturated two-dimensional (2D) Markov model to analyse the packet collision probability and the throughput performances of the stations (STAs) in a distributed coordination function network. Compared with the previous 2D models, it takes the flexible buffer size of the STA into consideration. Compared with the 3D models, it has the advantage of low complexity by avoiding matrix operations. From the numerical results, the authors explain the approximations used in the analytical models proposed in the common existing literatures, and discuss their effect on the model accuracy.
- Author(s): Salman A. AlQahtani
- Source: IET Communications, Volume 11, Issue 2, p. 177 –184
- DOI: 10.1049/iet-com.2016.0468
- Type: Article
- + Show details - Hide details
-
p.
177
–184
(8)
The deployment of billions of machine-to-machine (M2M) devices is expected to have an enticing effluence in cellular networks. Data aggregation is an attractive scheme to decrease power consumption; however, it introduces longer delay to the aggregated data. M2M devices have disparate traffic types with different delay requirements. In this study, the author proposes a priority-based data aggregation scheme at the M2M gateway that effectively maintains a good trade-off between the power consumption and delay requirement. An analytical model that considers the idle and busy states behaviour of the aggregator using preemption M/G/1 queuing with priority disciplines is developed and analysed. The performance measures in terms of system delay and power consumption are derived and used to quantify the trade-off between M2M delay sensitive traffic and low power consumption provisions. Based on the numerical and simulation results, the proposed scheme provides a good trade-off between delay and power consumption.
- Author(s): Tamer Soliman ; Fengfan Yang ; Saqib Ejaz ; Amir Almslmany
- Source: IET Communications, Volume 11, Issue 2, p. 185 –191
- DOI: 10.1049/iet-com.2016.0915
- Type: Article
- + Show details - Hide details
-
p.
185
–191
(7)
Recently, it is shown that the channel polarisation phenomenon of Arikan's polar codes with their original multilevel construction happens in several levels with perfect, partially perfect and useless bit channels. On the basis of this construction, this study aims to illustrate design principles and decoding steps of cooperative decode-and-forward polar coding schemes for half-duplex relay channel. In these schemes, the authors consider the use of relay retransmission of partially perfect bit channels in time-division process. The source node transmits its polar-coded information to both the relay and the destination nodes during the first time slot. For the second transmission period, the relay first decodes the source signal then after reconstruction of the polarisation matrix, the extracted partially perfect bit channels are recoded using another polar code and finally transmitted to the destination node. At destination, the signals received from both source and relay nodes are processed by using multi-stage successive cancellation decoding for retrieving the original information bits. They demonstrate via numerical results that by carefully constructed polarisation matrix at relay node, their cooperative polar coding schemes can achieve better performances than other previous schemes.
- Author(s): Xiangli Liu ; Jianhuan Wang ; Zan Li ; Jiangbo Si
- Source: IET Communications, Volume 11, Issue 2, p. 192 –197
- DOI: 10.1049/iet-com.2016.0063
- Type: Article
- + Show details - Hide details
-
p.
192
–197
(6)
This study considers the effect of channel estimation error (CEE) on the soft-output bit log-likelihood ratio (LLR) in a multiple-input–multiple-output detection system which the source sends their quadrature amplitude modulation to the detector through Rayleigh fading channels. The new expressions of LLR with maximum-likelihood CE for deterministic channel model and minimum mean square error (MMSE) CE for random channel model are obtained separately for linear MMSE receiver using known pilot-symbol-aided CE. Meanwhile, the optimal power allocation between training and data transmissions for these two different LLR expressions, which attends to get the maximum ratio of signal and interference plus noise ratio, are obtained under the total transmitting power constraints. Numerical results show that the power allocation ratio sets to be ∼0.5 is optimal for two new different LLRs at the same total power and system noise. Moreover, the derived LLR expressions match the simulation result and outperform the conventional system without the consideration of CEE and optimal power allocation. Meanwhile, the system performance is better than the existing research with the consideration of CE.
- Author(s): Weiliang Han ; Jianhua Ge ; Fengchen Ouyang ; Chensi Zhang ; Fengkui Gong
- Source: IET Communications, Volume 11, Issue 2, p. 198 –204
- DOI: 10.1049/iet-com.2016.0273
- Type: Article
- + Show details - Hide details
-
p.
198
–204
(7)
Traditional vector orthogonal frequency division multiplexing (V-OFDM) can obtain both multi-path diversity and outage gain by transforming an inter-symbol interference (ISI) channel into multiple ‘ISI-free’ channel vectors. To achieve full multi-path diversity and acquire better outage performance, a low-complexity precoding scheme combined with simple minimum mean square error (MMSE) equalisation for V-OFDM system is proposed in this study. First, the upper mutual information bound of the V-OFDM system is derived with channel state information at transmitter. Based on the upper bound, an optimal precoding scheme for V-OFDM is presented. Meanwhile, the closed-form and asymptotic expressions on outage probability of the proposed scheme are derived. Simulations show that this low-complexity scheme can achieve full multi-path diversity and result in lower outage probability than the traditional V-OFDM scheme. Besides, the proposed scheme in ISI fading channel is capable of approaching the upper bound with <0.1 bits/s/Hz performance gap and improving average channel capacity with 2 bits/s/Hz over the traditional V-OFDM scheme.
- Author(s): Xuewen Qian ; Yansha Deng ; Honggui Deng ; Yue Hu ; Chaoyang Zhang ; Jie Du
- Source: IET Communications, Volume 11, Issue 2, p. 205 –210
- DOI: 10.1049/iet-com.2016.0899
- Type: Article
- + Show details - Hide details
-
p.
205
–210
(6)
Visible light communication (VLC) system based on orthogonal frequency division multiplexing (OFDM) is promising for its ability to link a huge number of devices with high reliability and low latency. However, OFDM-based VLC systems are very sensitive to the symbol timing offsets. Thus, synchronisation algorithm is very important for OFDM-based VLC system. In this study, the authors first propose zero correlation code pair (ZCC pair) and investigate the periodical impulse-shaped correlation property of ZCC pair. Then the authors propose a novel timing offset estimation algorithm based on ZCC pair. The preamble is processed via peak-to-average power ratio (PAPR) reduction algorithms to overcome the PAPR problem in VLC systems. This algorithm achieves high accuracy and has low synchronisation error probability. The effectiveness of the authors’ proposed algorithm has been demonstrated using computer simulation under non-light-of-sight VLC and Gaussian channels. The results show that the authors’ algorithm outperforms the Schmidl Cox's and Park's algorithms in terms of synchronisation error probability and mean square error of timing error.
- Author(s): Koosha Pourtahmasi Roshandeh ; Ali Kuhestani ; Masoud Ardakani ; Chintha Tellambura
- Source: IET Communications, Volume 11, Issue 2, p. 211 –217
- DOI: 10.1049/iet-com.2015.1029
- Type: Article
- + Show details - Hide details
-
p.
211
–217
(7)
The authors study the transmit power allocation (PA) problem for a network of two multi-antenna terminals (one of which is a massive multiple-input and multiple-output (MIMO) terminal) and a two-way, amplify-and-forward relay. The relay is limited to a single antenna. Using perfect channel state information, the terminals employ beamforming with maximum-ratio-transmission and maximum-ratio-combining for transmission and reception, respectively. The authors investigate two practical problems, namely; (i) maximising the sum rate subject to a total power constraint (ii) maximising the sum rate when one of the terminals must exceed a target signal-to-noise ratio (SNR). For the first case, the authors derive the closed-form optimal PA and for the second, the authors derive a sub-optimal PA. In both cases, the resulting sum rates are a function of instantaneous channel gains. Thus by averaging over the Nakagami-m distribution and exploiting the weak law of large numbers, the authors derive the closed-form ergodic sum rates. Finally, the simulation results validate the theoretical analysis and show the sum-rate improvements over uniform PA. For example, to achieve 4 bit/s/Hz, a uniform allocation needs 1 dB more than the authors’ optimal allocation. When one of the SNRs must exceed a target value, the gap between the authors’ sub-optimal PA and random PA increases to 2 dB.
- Author(s): Changshan Chen and Xinsheng Zhao
- Source: IET Communications, Volume 11, Issue 2, p. 218 –224
- DOI: 10.1049/iet-com.2016.0460
- Type: Article
- + Show details - Hide details
-
p.
218
–224
(7)
The handoff rate under base stations (BSs) cooperation for the user's two transitions in ultra-dense network (UDN) is analysed in this study. Frequent handoffs in UDN cause the degradation of user experience, which should be considered for UDN deployment. The determination of cooperation area to prevent the handoff of the first transition (from the origin to the first destination) is investigated and an approximate form that is convenient for practical application is given out. The handoff rate of the second transition (from the first destination to the second) is then studied with the BSs cooperation. Some special cases, where the mobility angle is set at some fixed values are also investigated. It is shown that the handoff rate is significantly affected by both the direction and the length of the user's transition. Moreover, the correlation between the two transitions does impact on the performance of handoff rate under the BSs cooperation. Numerical results are finally presented to verify the authors’ analysis.
- Author(s): Wassim Ben Chikha ; Slim Chaoui ; Rabah Attia
- Source: IET Communications, Volume 11, Issue 2, p. 225 –231
- DOI: 10.1049/iet-com.2016.0335
- Type: Article
- + Show details - Hide details
-
p.
225
–231
(7)
The automatic modulation identification of a detected signal represents an essential task for an intelligent receiver and plays an important role in demodulating the intercepted signals for several communication systems. In this study, the authors propose an efficient algorithm of superposed modulations identification dedicated for two-way relaying multiple-input multiple-output systems with physical-layer network coding (PLNC). The aim of this work is to identify a pair of sources modulations from the superposed constellation, when PLNC is applied. For this purpose, the authors use the higher order statistics-based features in conjunction with genetic algorithm and information theory as a features selection method and the random forests as a classifier. Simulations are provided to assess the accuracy of the proposed algorithm through the average probability of correct identification for different modulation scheme pairs. It is shown that the algorithm achieves high-modulation identification in acceptable signal-to-noise ratio level at different relay position.
- Author(s): Emad S. Hassan
- Source: IET Communications, Volume 11, Issue 2, p. 232 –241
- DOI: 10.1049/iet-com.2016.0655
- Type: Article
- + Show details - Hide details
-
p.
232
–241
(10)
Coordinated multi-point (CoMP) transmission is a promising technique for improving spectral efficiency and overall system throughput in future cellular communication systems. This study investigates the downlink performance of relay-assisted CoMP transmissions. The non-ideal transceiver scenario that considers the effects of hardware impairments on the performance of CoMP transmission is presented. The performance of relay-assisted CoMP transmission using a hybrid opportunistic cooperative (HOC) protocol is evaluated and compared for two different CoMP transmission strategies: coordinated beam-forming and joint processing (JP). For each strategy, the performance in terms of outage probability, average sum rate and throughput is studied. The non-COMP strategy is also included for comparison. Both theoretical and simulation results are considered to test the performance of ideal and practical scenarios of both CoMP transmission using HOC protocol and other relaying protocols such as amplify-and-forward (AF) and decode-and-forward (DF) protocols. The obtained results show that the HOC protocol with ideal scenario, significantly improves the average sum rate, the net throughput and the outage probability of CoMP transmission especially when considering the JP strategy. The obtained results also indicate that, the performance degradation due to non-ideal transceiver with HOC protocol is small when compared with AF and DF protocols.
- Author(s): Li Lu ; Desheng Wang ; Yingzhuang Liu
- Source: IET Communications, Volume 11, Issue 2, p. 242 –248
- DOI: 10.1049/iet-com.2016.0767
- Type: Article
- + Show details - Hide details
-
p.
242
–248
(7)
In a densely deployed small-cell network, part of small-cell base stations (BSs) are activated to serve users while the rest are sleep to save energy. The uplink performance region is studied here for such network employing orthogonal frequency-division multiple access. The authors characterise the limit of performance region using the Pareto boundary. This boundary describes all achievable performance results of beamformers and power allocation. Enabling BS allocation increases the spatial degree of freedom by cooperative reception but greatly complicates searching boundary of performance region. To overcome the complexity challenge, a fast and customised iterative algorithm is developed to check if an arbitrary given performance target is feasible. Using the proposed feasibility checking, the authors can characterise the Pareto-optimal boundary of uplink performance with activated BS allocation. The authors further study two types of BS allocation schemes, namely the network-centric and user-centric strategies. Comparison of both strategies is illustrated in the authors’ numerical examples.
- Author(s): Yuhao Hua ; Guannan Zhao ; Wenjing Zhao ; Minglu Jin
- Source: IET Communications, Volume 11, Issue 2, p. 249 –257
- DOI: 10.1049/iet-com.2016.0122
- Type: Article
- + Show details - Hide details
-
p.
249
–257
(9)
Two kinds of modified codewords for space–time block coded spatial modulation (STBC-SM) are presented in this study. The first modified codeword introduces a concept of flexible coefficients into the M-ary phase shift keying STBC-SM. A method is proposed to obtain the optimal flexible coefficients. Moreover, the first modified codewords can also be applied to the systems developed from the STBC-SM. In the second provided codewords, super-orthogonal space–time trellis codes are applied in STBC-SM. Therefore, a higher spectral efficiency is obtained compared with the original STBC-SM. Finally, the simulation results and theoretical analysis demonstrate these performance advantages of the two kinds of modified codewords for STBC-SM.
- Author(s): Chiapin Wang ; Shih-Hau Fang ; Wen-Hsing Kuo ; Hsiao-Chun Wu
- Source: IET Communications, Volume 11, Issue 2, p. 258 –266
- DOI: 10.1049/iet-com.2016.0082
- Type: Article
- + Show details - Hide details
-
p.
258
–266
(9)
In this study, the authors tackle the problem of carrier aggregation (CA) in downlink of long-term evolution advanced (LTE-A) femtocell networks. They propose a novel approach in a new perspective: namely, user navigation, to improve the CA performance of an LTE-A system in the indoor environment. The proposed indoor user navigation (IUN) algorithm exploits the a priori knowledge of radio interferences between femtocells to build a geometric quality-of-service (QoS) map, which can be utilised to navigate users toward the locations suitable for performing CA to satisfy the QoS requirements. The simulations demonstrate the effectiveness of the proposed IUN algorithm to improve the CA performance in terms of the aggregate throughput for the LTE-A femtocell networks.
- Author(s): Yu-Chieh Chen ; Jen-Wei Chang ; Cho-Hsin Tsai ; Guang-Xun Lin ; Hung-Yu Wei ; Fu-Ming Yeh
- Source: IET Communications, Volume 11, Issue 2, p. 267 –272
- DOI: 10.1049/iet-com.2016.0886
- Type: Article
- + Show details - Hide details
-
p.
267
–272
(6)
The development of indoor small cell provides network operators with new opportunities to address surging mobile data traffic, coverage infill and capacity boost scenarios, and finally results in growing expectations relative to quality of experience (QoE). However, the deployment of indoor small cell base station also raises some resource allocation issues. This study aims to propose an max-utility resource allocation mechanism that maximises all users’ utility for indoor small cell networks. The objective of the proposed max-utility resource allocation algorithm is to optimise the total user's QoE while guaranteeing as many as possible users can enjoy their request service at an acceptable quality. This is achieved by considering user's QoE state and signal strength into the resource allocation algorithm. Multiservice scenario is also considered in the proposed max-utility resource allocation algorithm. To compare the performance of the proposed max-utility resource allocation mechanism with round-robin, max-throughput and max-minMOS approach, a simulation analysis is implemented. The simulation result showed that the proposed strategy achieves the best average utility compared with other approaches. Result also showed that the proposed strategy is suitable for indoor small cell networks under various kinds of scenarios with different user behaviours and network topologies.
- Author(s): Weiwei Yang and Xiaohui Zhao
- Source: IET Communications, Volume 11, Issue 2, p. 273 –281
- DOI: 10.1049/iet-com.2016.0742
- Type: Article
- + Show details - Hide details
-
p.
273
–281
(9)
In this study, the authors study the robust resource allocation problem for orthogonal frequency division multiplexing-based cooperative cognitive radio networks (CRNs) with decode and forward protocol and consideration of imperfect channel state information. The objective is to maximise the capacity of the cooperative CRN, while the interference to primary user receiver is below a predefined interference threshold and the transmit power of cognitive source and each relay is kept within their power budgets. Considering all possible channel uncertainties, they propose a heuristic robust relay selection scheme and formulate robust power allocation as a semi-infinite programming (SIP). By the worst-case approach, the SIP problem is converted into a convex optimisation problem and solved by the Lagrange dual decomposition method. They also analyse feasible regions of the constraints, convergence behaviour and computational complexity of their proposed robust algorithm. Simulation results show the impact of channel uncertainties and the outperformance of the proposed algorithm by comparing with non-robust algorithms.
- Author(s): Wanguo Jiao and Guoqing Liu
- Source: IET Communications, Volume 11, Issue 2, p. 282 –291
- DOI: 10.1049/iet-com.2016.1069
- Type: Article
- + Show details - Hide details
-
p.
282
–291
(10)
The performance analysis is important for quality of service (QoS) guarantee, which has not been well studied in the interference-limited system. The authors study the QoS performance of each user in an interference-limited system when the power control policy is used to maximise the sum rate of users. Since service processes of users are correlated, the authors first propose a two-dimensional Markov chain to model the transition among queue states of users. Through solving the Markov chain, the authors derive the closed-form formulae of the stationary probability of the queue length and other QoS metrics of each user. The analysis results indicate that the power allocation problem should be reconsidered in unsaturated networks since the power allocation policy designed for saturated networks is no longer appropriate. The authors thus develop a new power allocation algorithm which considers queue length and channel quality jointly. Finally, the simulation results verify that the authors’ analytical method provides accurate estimations of QoS metrics and the proposed algorithm enhance the power efficiency and improve the queue performance of each user.
- Author(s): Zhenyu Zhang ; Fengchun Tian ; Fanxin Zeng ; Shibiao He ; Guixin Xuan
- Source: IET Communications, Volume 11, Issue 2, p. 292 –301
- DOI: 10.1049/iet-com.2016.0711
- Type: Article
- + Show details - Hide details
-
p.
292
–301
(10)
A complementary M-ary orthogonal spreading (CMOS) architecture with orthogonal frequency division multiplexing (OFDM) is proposed to improve performance of bit-error rate (BER) and spectrum efficiency for high frequency (HF) communications. The CMOS-OFDM architecture is based on orthogonal complementary pairs with their central elements being zero. It is well known that complementary pairs theoretically reduce peak-to-mean envelope power ratio (PMEPR) of OFDM due to their ideal aperiodic auto-correlation properties. However, many practical OFDM applications, such as HF OFDM and IEEE 802.11, require that no data should be modulated to direct current (DC) subcarrier, which will destroy ideal properties of traditional complementary pairs and hence increase their PMEPRs. Compared with traditional complementary pairs, the proposed zero-centre complementary pairs (ZCCPs) in CMOS-OFDM architecture may maintain ideal properties and hence be more suitable for OFDM systems as long as zero element in the centre is modulated to DC subcarrier. The corresponding simulation results and numerical analyses over the HF fading channel modelled by ITU-R F.1487 are provided. Different from the previous researches on HF OFDM systems, the proposed HF CMOS-OFDM architecture using the constructed ZCCPs not only possesses excellent BER performance, but also may firmly resist PMEPR to 3 dB or near to 3 dB.
- Author(s): Pengfei Shao ; Yanwei Zhao ; Mingxia Yang ; Zhe Wang
- Source: IET Communications, Volume 11, Issue 2, p. 302 –309
- DOI: 10.1049/iet-com.2016.0484
- Type: Article
- + Show details - Hide details
-
p.
302
–309
(8)
This study is concerned with the network coding (NC) problem in error-prone wireless multicast networks. A hash searching and NC-based constant retransmission scheme (HSNCR) is proposed to make combination selection, where the retransmission of the packet losses can be carried out during the whole process of original packet transmission, and thus the HSNCR can increase the possibility of NC. Furthermore, this new scheme maximises the efficiency of every retransmission by only retransferring an optimum combination or maximum combination of original lost packets. To support HSNCR, an efficient hash searching approach is also designed for the combination selection of original lost packets. Simulation results show that the authors’ proposed scheme indeed outperforms previous works in reducing the number of retransmission.
Cloud service reliability modelling and optimal task scheduling
Two-dimensional distributed coordination function model with finite buffer sizes
Analysis and modelling of power consumption-aware priority-based scheduling for M2M data aggregation over long-term-evolution networks
Decode-and-forward polar coding scheme for receive diversity: a relay partially perfect retransmission for half-duplex wireless relay channels
Soft-output MMSE MIMO detector under different channel estimation models
Achieving upper mutual information bound precoding for V-OFDM with MMSE receiver
Synchronisation algorithm based on zero correlation code pair for OFDM-based VLC systems
Ergodic sum rate analysis and efficient power allocation for a massive MIMO two-way relay network
Performance of handoff rate for two transitions under base stations cooperation in ultra-dense network
Identification of superposed modulations for two-way relaying MIMO systems with physical-layer network coding
Performance analysis of relay-assisted CoMP transmissions with non-ideal transceiver
Characterisation of Pareto boundary for uplink small-cell base stations allocation: a fast iterative algorithm
Modified codewords design for space–time block coded spatial modulation
Indoor user navigation for CA in LTE-advanced
Max-utility resource allocation for indoor small cell networks
Robust resource allocation for orthogonal frequency division multiplexing-based cooperative cognitive radio networks with imperfect channel state information
Performance analysis and power allocation for the unsaturated two-user interference channel
Complementary M-ary orthogonal spreading OFDM architecture for HF communication link
Hash searching and network coding based constant retransmission for wireless multicast
Most viewed content
Most cited content for this Journal
-
A review on security threats, vulnerabilities, and counter measures of 5G enabled Internet‐of‐Medical‐Things
- Author(s): Mohammad Kamrul Hasan ; Taher M. Ghazal ; Rashid A. Saeed ; Bishwajeet Pandey ; Hardik Gohel ; Ala’ A. Eshmawi ; S. Abdel‐Khalek ; Hula Mahmoud Alkhassawneh
- Type: Article
-
Compressive sensing-based coprime array direction-of-arrival estimation
- Author(s): Chengwei Zhou ; Yujie Gu ; Yimin D. Zhang ; Zhiguo Shi ; Tao Jin ; Xidong Wu
- Type: Article
-
Massive MIMO: survey and future research topics
- Author(s): Daniel C. Araújo ; Taras Maksymyuk ; André L.F. de Almeida ; Tarcisio Maciel ; João C.M. Mota ; Minho Jo
- Type: Article
-
Performance analysis of non-orthogonal multiple access in downlink cooperative network
- Author(s): Jinjin Men and Jianhua Ge
- Type: Article
-
Non-orthogonal multiple access schemes with partial relay selection
- Author(s): Sunyoung Lee ; Daniel Benevides da Costa ; Quoc-Tuan Vien ; Trung Q. Duong ; Rafael Timóteo de Sousa Jr.
- Type: Article