Online ISSN
1751-8636
Print ISSN
1751-8628
IET Communications
Volume 5, Issue 15, 14 October 2011
Volumes & issues:
Volume 5, Issue 15
14 October 2011
-
- Author(s): A.C. Talay and D.T. Altilar
- Source: IET Communications, Volume 5, Issue 15, p. 2097 –2105
- DOI: 10.1049/iet-com.2010.0285
- Type: Article
- + Show details - Hide details
-
p.
2097
–2105
(9)
Advancement of cognitive radio (CR) technology can overcome the problems encountered from bandwidth and spectrum access limitations because of tremendous potential to improve the utilisation of the radio spectrum by efficiently reusing and sharing the licensed spectrum bands, as long as the interference power inflicted on the primary users of the band remains below a predefined threshold level. In mobile CR ad hoc networks, routing is one of the most important issues to be addressed and desires deep investigation. In this study, a distributed and efficient cluster-based spectrum and interference aware routing protocol is proposed. The protocol incorporates the spectrum availability cost and interference metrics into the routing algorithm to find better routes. A route preservation method is also implemented to repair the route when it is defective because of primary user activity. Extensive experimental evaluations are performed in the ns2 simulator. Results of the simulations illustrate that, the proposed algorithm can well fit into the mobile CR ad hoc networks and improve the network performance. The results indicate that the proposed protocol provides better adaptability to the environment than the existing ones. It also increases throughput and reduces data delivery latency in a number of realistic scenarios and outperforms recently proposed routing protocols for CR networks. - Author(s): K.P. Peppas ; C.K. Datsikas ; N.C. Sagias ; G.S. Tombras
- Source: IET Communications, Volume 5, Issue 15, p. 2106 –2115
- DOI: 10.1049/iet-com.2010.0305
- Type: Article
- + Show details - Hide details
-
p.
2106
–2115
(10)
The authors study the performance of a dual-hop plus a direct link multiple-input multiple-output (MIMO) wireless communication system using orthogonal space–time block codes. The system under consideration is based on the decode-and-forward relaying protocol and operates over spatially correlated Nakagami-m fading channels. The proposed analysis is generic enough to account for any MIMO correlation model either from measurements or having theoretical and analytical justification. Analytical expressions for the system end-to-end outage and average symbol error probability are obtained, while critical parameters of the MIMO channel are taken into consideration such as the angle of arrival, the antenna array configuration, the wavelength and non-isotropic scattering conditions. Various numerical and computer simulation results demonstrate the proposed mathematical analysis and the impact of the above parameters to the system performance. - Author(s): A.R. Hedayati ; M.N. Fesharaki ; K. Badie ; V. Aghazarian
- Source: IET Communications, Volume 5, Issue 15, p. 2116 –2124
- DOI: 10.1049/iet-com.2010.0931
- Type: Article
- + Show details - Hide details
-
p.
2116
–2124
(9)
The increasing applications of networking have caused limitation of dynamic bandwidth allocation (DBA) in next generation access networks such as Ethernet passive optical network (EPON). In this paper, Arishtat, a novel EPON-based DBA method has been proposed that shows advantages over currently available methods. In Arishtat, which is based on the auction theory, optical line terminal runs an auction-based process to effectively register optical network units bandwidth requests and allocates the highest bidders based on the amount of available bandwidth. Simulation results indicate significant improvements comparing to Fair sharing using dual-service-level agreements, and ‘limited service’ interleaved polling with adaptive cycle time methods regarding quality of service parameters such as packet loss, throughput, line utilisation and the execution time of running method. - Author(s): K. Choi
- Source: IET Communications, Volume 5, Issue 15, p. 2125 –2129
- DOI: 10.1049/iet-com.2011.0131
- Type: Article
- + Show details - Hide details
-
p.
2125
–2129
(5)
A modified Alamouti-coded orthogonal frequency division multiplexing (OFDM) scheme is proposed for cooperative systems in non-selective fading environments. Even with the frequency offset between two distributed transmit antennas, the proposed scheme achieves ideal performance and full rate of Alamouti code. By switching subcarriers in the second OFDM symbol of each Alamouti-coded OFDM symbol pair after a simple-phase rotation in the first OFDM symbol, inter-carrier interference terms can be perfectly cancelled after a simple linear combining with the processing overhead of two times down-conversions and discrete Fourier transform (DFT) operations at each OFDM symbol. - Author(s): C. Liu ; O.W.W. Yang ; Y. Shu ; M. Li
- Source: IET Communications, Volume 5, Issue 15, p. 2130 –2140
- DOI: 10.1049/iet-com.2010.0278
- Type: Article
- + Show details - Hide details
-
p.
2130
–2140
(11)
When a node is not abiding by the rules of the protocol of a wireless network for its own benefit, it can cause severe degradation to network performance. Therefore it is important to detect such selfish behaviour. However, this is not an easy task. The main difficulty comes from the random operation of the carrier-sense multiple-access with collision avoidance (CSMA/CA) protocol, and is exacerbated by the nature of the wireless medium itself. The authors propose in this study a simple and quick algorithm, called sliding window non-parametric cumulative sum (SWN-CUSUM), to detect selfish nodes that deliberately modify its backoff window to gain unfair access to the network resources. SWN-CUSUM uses a sliding window to prevent unlimited build-up of the cumulating sum used in the protocol. The efficiency of this detection algorithm has been validated by extensive simulations using a Qualnet simulator. Comparative analysis of the proposed algorithm with a traditional CUSUM method demonstrates its superior performance with high detection accuracy and low false alarm rate. In addition, the authors compared SWN-CUSUM with other detection techniques, such as sequential probability ratio test and exponentially weighted moving average, the results show that our algorithm has a good performance in detection delay. - Author(s): Y. Liu ; J. Liu ; H. Chen ; L. Zheng ; G. Zhang ; W. Guo
- Source: IET Communications, Volume 5, Issue 15, p. 2141 –2148
- DOI: 10.1049/iet-com.2010.1094
- Type: Article
- + Show details - Hide details
-
p.
2141
–2148
(8)
In this study, the authors investigate the downlink performance of distributed antenna systems (DAS) in multicell environment with blanket transmission. In most existing works, the interference plus noise is treated as Gaussian random variable with fixed variance by the central limit theorem. However, doing this will ignore the effect of the short-term fading on interference that is called as restrictive condition. To avoid the restrictive condition, the authors consider the variance of interference plus noise as a random variable with changeable variance that is influenced by the short-term fading when propagation pathloss and transmit power are given. From the perspective of information theoretic, the closed-form and approximate analytical expressions of downlink achievable throughput, outage probability and average bit error rate in the cellular system are derived for no-shadowing and shadowing scenarios, respectively. Extensive simulation results validate the theoretical analysis and demonstrate that the system performances can be significantly improved for cell-edge users. Moreover, the proposed analytical method can obtain more accurate system performances. - Author(s): J.-H. Lee ; T. Ernst ; D.-J. Deng ; H.-C. Chao
- Source: IET Communications, Volume 5, Issue 15, p. 2149 –2156
- DOI: 10.1049/iet-com.2011.0015
- Type: Article
- + Show details - Hide details
-
p.
2149
–2156
(8)
As Internet Protocol (IP) multicast allows the efficient use of network bandwidth for multipoint communication, it is expected to be an essential communication type for delivering multimedia services to mobile nodes (MNs). In this study, the authors address an issue of consumer multicast traffic support in a Proxy Mobile IPv6 (PMIPv6) environment wherein network-based mobility management is deployed for MNs. The recently standardised PMIPv6 multicast listener support provides options for deploying multicast listener functions in a PMIPv6 domain, whereas it does not address specific optimisations and efficiency improvements of multicast routing. The authors first review the PMIPv6 multicast listener support and point out the limitations of the current approach. Then, propose an improved multicast handover procedure that optimises multicastgroup management by utilising the context of consumer's MN running multicast applications. The authors develop analytical models to evaluate the proposed multicast handover procedure compared with the base one. From the conducted analysis, it is demonstrated that the proposed multicast handover procedure minimises the service interruption time and prevents the multicast packet loss during handovers. Furthermore, in terms of signalling cost consumption, the proposed multicast handover procedure operates on an equal basis with the base one. - Author(s): G. Manglani and A.K. Chaturvedi
- Source: IET Communications, Volume 5, Issue 15, p. 2157 –2166
- DOI: 10.1049/iet-com.2010.0599
- Type: Article
- + Show details - Hide details
-
p.
2157
–2166
(10)
The authors propose a new multi-tone (MT) code division multiple access (CDMA) design which has a superior bit error rate (BER) performance than conventional MT CDMA in the presence of frequency offset. The design involves multiplexing of Walsh codes onto the sub-carriers in conjunction with double differential modulation. To exploit the full potential of the design a partial correlation receiver has been proposed. Depending on the signal-to-noise ratio (SNR) and frequency offset it is possible to tune this receiver for the best possible performance. The simulated BER performance of the proposed system has been found to be better than MT CDMA for small as well as large frequency offsets for both single and multi-user systems in additive white Gaussian noise (AWGN) and Rayleigh fading channels. - Author(s): S.Y. Chang ; H.-C. Wu ; Y. Wu ; H.-C. Chao
- Source: IET Communications, Volume 5, Issue 15, p. 2167 –2176
- DOI: 10.1049/iet-com.2011.0025
- Type: Article
- + Show details - Hide details
-
p.
2167
–2176
(10)
Among various network topologies, tree-like networks, also known as hierarchical networks are proposed to decrease the overhead of the routing table especially for the situation involving many network nodes. Usually, the routing table size and the routing complexity are the two crucial concerns in designing a large network. Although there have been various algorithms to optimise the routing strategies for the hierarchical networks, hardly exists any work in studying and evaluating the routing table size and the routing complexity rigorously in the statistical sense. In this study, the authors generalise a new mathematical framework by applying the point process in random geometry. The new framework proposed by the authors leads to the explicit statistical measures of the routing table size and the routing complexity, which can be specified as the functions of the hierarchical network parameters including the number of the hierarchical levels and the cluster population for each hierarchical level. After the relationship between the network topology and these two network performance measures (routing complexity and routing table size) is established, a cluster-population optimisation method for hierarchical networks is presented. The simulation results are also provided to demonstrate the advantage of a hierarchical network over the associated conventional network without hierarchy. - Author(s): Z. Cui ; Z. Wang ; X. Zhang
- Source: IET Communications, Volume 5, Issue 15, p. 2177 –2186
- DOI: 10.1049/iet-com.2010.1002
- Type: Article
- + Show details - Hide details
-
p.
2177
–2186
(10)
Layered decoding is well appreciated in low-density parity-check (LDPC) decoder implementation since it can achieve effectively high decoding throughput with low computation complexity. This work, for the first time, addresses low-complexity column-layered decoding schemes and very-large-scale integration (VLSI) architectures for multi-Gb/s applications. At first, the min-sum algorithm is incorporated into the column-layered decoding. Then algorithmic transformations and judicious approximations are explored to minimise the overall computation complexity. Compared to the original column-layered decoding, the new approach can reduce the computation complexity in check node processing for high-rate LDPC codes by up to 90% while maintaining the fast convergence speed of layered decoding. Furthermore, a relaxed pipelining scheme is presented to enable very high clock speed for VLSI implementation. Equipped with these new techniques, an efficient decoder architecture for quasi-cyclic LDPC codes is developed and implemented with 0.13 µm VLSI implementation technology. It is shown that a decoding throughput of nearly 4 Gb/s at a maximum of 10 iterations can be achieved for a (4096, 3584) LDPC code. Hence, this work has facilitated practical applications of column-layered decoding and particularly made it very attractive in high-speed, high-rate LDPC decoder implementation. - Author(s): F. Wang ; D. Li ; Y. Zhao
- Source: IET Communications, Volume 5, Issue 15, p. 2187 –2195
- DOI: 10.1049/iet-com.2010.1007
- Type: Article
- + Show details - Hide details
-
p.
2187
–2195
(9)
The release of IEEE 802.15.4 medium access control and physical layer specifications, employing carrier sense multiple access/collision avoidance (CSMA/CA) strategies, represents a significant milestone in promoting deployment of wireless sensor networks. In this study, the authors first analyse the performance of the slotted CSMA/CA strategy specified in the contention access period (CAP) of IEEE 802.15.4 by integrating the discrete-time Markov chain models of the node states and the channel states; and then, extend the Markov chain models by adopting a modification to the CAP. The extended models could be used to analyse the performance of the unslotted CSMA/CA strategy specified in IEEE 802.15.4 as well as that of the slotted CSMA/CA strategy. Extensive simulations demonstrate the accuracy and effectiveness of the proposed models and conclusions. - Author(s): S. Agathos and E. Papapetrou
- Source: IET Communications, Volume 5, Issue 15, p. 2196 –2205
- DOI: 10.1049/iet-com.2010.0259
- Type: Article
- + Show details - Hide details
-
p.
2196
–2205
(10)
Broadcasting is a key component of several networking mechanisms in mobile ad hoc networks. However, its traditional implementation suffers from resource consumption caused by message redundancy. Several efficient algorithms have been proposed to tackle this problem. Among them, the class of algorithms that construct on-demand a connected dominating set, known as dominant pruning, yields an improved performance. Dominant pruning algorithms capitalise on neighbourhood information and the previous hop of the broadcast message in order to minimise the set of nodes that forward a message. The proposed algorithm makes the observation that all the nodes, visited by a broadcast message, may be exploited in order to minimise the cost of broadcasting. The analysis of the proposed algorithm as well as extensive simulation results confirm the rationale behind the proposed approach and prove the performance gains. - Author(s): Y. Li ; L. Wang ; T.-K. Truong
- Source: IET Communications, Volume 5, Issue 15, p. 2206 –2211
- DOI: 10.1049/iet-com.2011.0318
- Type: Article
- + Show details - Hide details
-
p.
2206
–2211
(6)
A new decoder is proposed to decode the (23, 12, 7) binary Golay-code up to five errors. It is based on the algorithm that can correct up to four errors for the (24, 12, 8) extended Golay-code proposed by Lin et al., thereby achieving the soft decoding in the real sense for the Golay-code. For a weight-2 or weight-3 error pattern decoded by the hard decoder for correcting up to three errors, one can find the corresponding 21 weight-4 or weight-5 error patterns and choose the one with the maximum emblematic probability value, which is defined as the product of individual bit-error probabilities corresponding to the non-zero locations of the error pattern as the ultimate choice. Finally, simulation results of this decoder over additive white Gaussian noise (AWGN) channels show that the proposed method provides 0.9 dB coding gain than that of Lin et al.'s algorithm at bit-error rate of 10−5. - Author(s): A. Naanaa and S. Belghith
- Source: IET Communications, Volume 5, Issue 15, p. 2212 –2220
- DOI: 10.1049/iet-com.2011.0002
- Type: Article
- + Show details - Hide details
-
p.
2212
–2220
(9)
In this study, the authors propose a method to minimise the multi-user interference (MUI) caused by multiple access (MA) in a time hopping ultra-wide-band (TH-UWB) system with line-of-sight (LOS) multi-path channel in a residential environment IEEE 802.15.4a channel model. The authors considered both synchronous and asynchronous cases. The problem is formulated as a combinatorial optimisation problem (COP) and solved by means of an efficient optimisation algorithm called guided local search (GLS). The optimisation criterion is the average collision number (ACN). The code optimisation method is validated by simulating the system and computing the binary error rate. - Author(s): G. Fei and G. Hu
- Source: IET Communications, Volume 5, Issue 15, p. 2221 –2230
- DOI: 10.1049/iet-com.2010.0455
- Type: Article
- + Show details - Hide details
-
p.
2221
–2230
(10)
Understanding the topology of a network is very important for network control and management. There have been several methods designed for estimating network topology from end-to-end measurements. Among these methods, the maximum-likelihood-based topology inference method is superior to suboptimal and pair-merging approaches, because it is capable of finding the global optimal topology. However, the existing method which searches the maximum likelihood tree directly is time-consuming, and may not be able to obtain the accurate topology of a larger-scale network. To overcome these issues, this study presents a maximum-likelihood-based leaf nodes inserting topology inference method. The method first builds a binary tree with two leaf nodes, and then inserts the remaining nodes into the tree one by one according to the maximum-likelihood criterion. When compared with the previous methods, the proposed method has the advantages of less computational cost and higher estimate precision. The analytical and simulation results show good performances by the proposed method. - Author(s): K. Chen and C. Hu
- Source: IET Communications, Volume 5, Issue 15, p. 2231 –2240
- DOI: 10.1049/iet-com.2010.0432
- Type: Article
- + Show details - Hide details
-
p.
2231
–2240
(10)
Network measurement projects such as NLANR, Routeviews and RIPE have greatly advanced people's ability to understand, manage and engineer the Internet. Meanwhile, the significant maintenance fee to support such monitoring infrastructures motivates us to think about a cost-effective way to manage these systems. In this study, the authors measure, model and evaluate the border gateway protocol (BGP) monitoring system (BGPMon) that is mainly composed of vantage point ASes (i.e. monitors or VPs) peered with Routeviews and RIPE. The results from the authors’ experiments show the feasibility to use fewer VPs while still retaining the original monitoring capability of the existing BGPMon. Only 110 VPs out of the original 438 ones are capable of monitoring most of the information for all the six metrics with the optimum VP selection method given in this paper. The authors further evaluate the selected VPs at different times and observe that the performance is encouragingly stable, for example, more than 99% of the information for five out of the six metrics can be constantly captured with less than 110 VPs in random samples. - Author(s): A.J. Yuste ; A. Triviño ; E. Casilari ; F.D. Trujillo
- Source: IET Communications, Volume 5, Issue 15, p. 2241 –2249
- DOI: 10.1049/iet-com.2010.0692
- Type: Article
- + Show details - Hide details
-
p.
2241
–2249
(9)
Mobile ad hoc networks (MANETs) connected to the Internet require a gateway to operate. The gateway is responsible for providing the configuration parameters to the nodes by means of message exchanges. These messages are also necessary to create and/or update the route to the gateway in the mobile nodes. As MANET nodes move freely, these messages are generated at the beginning of the connections (to obtain the configuration parameters), when the route to the gateway breaks or when the gateway proactively sends them. This message exchange, also known as the gateway discovery procedure, has to be optimised in order to release wireless resources for the data transmissions. In this sense, this study proposes a novel technique by which the messages that the gateway periodically generates are exclusively forwarded in the areas where the links are expected to remain stable. By this, nodes are able to learn stable routes and, in turn, the messages generated because of the breakages of used links are avoided. From this parameter setting, the network performance is improved. The main difficulty of the technique is to determine the paths that are stable. For this purpose, the statistical characterisation of link duration in MANETs is employed in this study. The simulation results show the goodness of applying the proposed technique in terms of packet delivery ratio, protocol overhead and end-to-end delay. - Author(s): A.M. Elazreg and J.A. Chambers
- Source: IET Communications, Volume 5, Issue 15, p. 2250 –2255
- DOI: 10.1049/iet-com.2010.0291
- Type: Article
- + Show details - Hide details
-
p.
2250
–2255
(6)
In this study, a new sub-optimum detection scheme is proposed which employs closed-loop extended orthogonal space–time block coding and outer convolutive coding within an asynchronous cooperative wireless relay network to achieve full data rate and full diversity gain between the relays and destination node together with coding gain. Simulation results confirm that the proposed scheme can effectively suppress intersymbol interference induced by asynchronism between the relay nodes at the destination node.
United nodes: cluster-based routing protocol for mobile cognitive radio networks
Dual-hop multi-input multi-output relay systems over spatially correlated Nakagami-m fading channels
Arishtat: auction-based dynamic bandwidth allocation method in Ethernet passive optical networks
Inter-carrier interference-free Alamouti-coded OFDM for cooperative systems with frequency offsets in non-selective fading environments
Sliding window non-parametric cumulative sum: a quick algorithm to detect selfish behaviour in wireless networks
Downlink performance of distributed antenna systems in multicell environment
Improved PMIPv6 handover procedure for consumer multicast traffic
Multi-tone CDMA design for arbitrary frequency offsets using orthogonal code multiplexing at the transmitter and a tunable receiver
Theoretical analysis for tree-like networks using random geometry
Reduced-complexity column-layered decoding and implementation for LDPC codes
Analysis of CSMA/CA in IEEE 802.15.4
Efficient broadcasting using packet history in mobile ad hoc networks
Soft decoding of the (23, 12, 7) Golay-code up to five errors
Performance enhancement of a time hopping – pulse position modulation ultra-wide-band system using guided local search
Improving maximum-likelihood-based topology inference by sequentially inserting leaf nodes
Border gateway protocol monitoring system can be cost effective
Adaptive gateway discovery for mobile ad hoc networks based on the characterisation of the link lifetime
Sub-optimum detection scheme for asynchronous cooperative relay networks
Most viewed content for this Journal
Article
content/journals/iet-com
Journal
5
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
