Online ISSN
1751-8636
Print ISSN
1751-8628
IET Communications
Volume 6, Issue 10, 3 July 2012
Volumes & issues:
Volume 6, Issue 10
3 July 2012
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- Author(s): B. Allen ; D. Edwards ; B. Honary
- Source: IET Communications, Volume 6, Issue 10, p. 1145 –1146
- DOI: 10.1049/iet-com.2012.0210
- Type: Article
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- Author(s): V. Sipal ; B. Allen ; D. Edwards ; B. Honary
- Source: IET Communications, Volume 6, Issue 10, p. 1147 –1162
- DOI: 10.1049/iet-com.2011.0281
- Type: Article
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It has been 20 years since the word ultrawideband (UWB) has first been used in the open literature. In these 20 years, ideas have been transformed into real products. Yet, some might object that UWB has not yet lived upto the promises of gigabit wireless. This review shows that despite some drawbacks, UWB is not only needed because of the spectrum gridlock but it can still deliver its promises, including gigabit wireless. To do so, the gap between the potential, which is achievable, and the current performance must be closed. Thus, this review identifies some main issues of UWB (range, bit error rate performance, data rate, chip complexity and issues associated by strong narrowband interference). It shows that their reasons are well understood and addressed by erudite research, which includes low complexity chip design, alternative modulation schemes, multiple antenna systems, UWB radio-over-fibre, higher band UWB and interferer detection and suppression techniques. A specific feature of this review is the cross-layer approach. The latest findings from different system layers, for example, wave propagation, are linked to the system performance or complexity. - Author(s): M.A. Yusoff ; Z. Zang ; S.S. Abeysekera
- Source: IET Communications, Volume 6, Issue 10, p. 1163 –1169
- DOI: 10.1049/iet-com.2010.1055
- Type: Article
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Spectral efficiency is a major requirement in ultra-wideband (UWB) communication systems because of very low power spectral density (PSD) regulations imposed on the transmitted signals. Besides, large number of orthogonal waveforms is highly desirable in multiuser systems. In this study, the design of a set of spectrally efficient orthogonal waveforms is investigated. The design of UWB waveforms based on orthogonal Hermite–Rodriguez basis functions and linear frequency modulation (LFM) is proposed herein. The design is formulated as a quadratic semi-infinite programming problem with spectral and orthogonality constraints. Numerical examples are presented to illustrate the effectiveness of Hermite–Rodriguez-based waveforms with the proposed optimisation approach. Comparison with a recent result shows that the proposed approach compares favourably with those reported in the literatures in terms of the number of waveforms can be produced and the achievable spectral efficiency of the designed waveforms. - Author(s): V. Sipal ; B. Allen ; D. Edwards
- Source: IET Communications, Volume 6, Issue 10, p. 1170 –1178
- DOI: 10.1049/iet-com.2010.1080
- Type: Article
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This study explores the performance of multi-tone frequency shift keying (MT-FSK) in ultrawideband (UWB) wireless communications as an alternative to the standard modulation techniques. Its advantage is its ability to provide multiple user access even within the recently tightened regulations on UWB communications. Unlike previous works that discussed MT-FSK from the information theory perspective, here the possibility of practical implementation is explored. The basic system parameters such as tone bandwidth, number of frequencies and duty cycle are studied in terms of propagation characteristics, optimum data rate and system complexity. With optimum parameters, the authors show that a system using MT-FSK is capable of data transmission at a data rate of 250 Mbps with bit-error-rate below 10−5 whereas the receiver complexity is lower than for standard methods utilising the UWB spectrum by means of impulse radio or multi-band orthogonal frequency division multiplexing (OFDM). - Author(s): P.K. Gentner ; G.S. Hilton ; M.A. Beach ; C.F. Mecklenbräuker
- Source: IET Communications, Volume 6, Issue 10, p. 1179 –1186
- DOI: 10.1049/iet-com.2010.1054
- Type: Article
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An ultra-wideband (UWB) antenna array is designed to satisfy given constraints in a (large) contiguous frequency range. Space limitations are tight in many applications and it is often infeasible to design the antenna array with preferred element spacings of λ/2 at the centre frequency. In this study, the authors compare uniform linear UWB antenna arrays and non-uniform reduced-aperture UWB antenna arrays with more compact element spacings following a geometric progression. The authors analyse and discuss performance degradations with respect to irregularly spaced monopoles. The manufactured non-uniform linear UWB antenna arrays are characterised by measurements in an anechoic chamber. The results are correlated with the arrayfactor and compared with measured data of uniform linearly spaced monopoles in the time and frequency domains. It is found that a compact non-uniform linear UWB array with element spacings following a geometric progression can be designed such that its main lobe performs very close to that of a uniform linear array, with an antenna array size reduction of 23.6% for a seven-element non-uniform linear UWB array. - Author(s): W. Thompson ; R. Cepeda ; M.A. Beach ; S. Armour
- Source: IET Communications, Volume 6, Issue 10, p. 1187 –1194
- DOI: 10.1049/iet-com.2010.1057
- Type: Article
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This study investigates two areas relating to practical multi-antenna ultra-wideband (UWB) indoor channel: the frequency dependency in line-of-sight (LOS) and non-LOS (NLOS) environments, and the differences in spatial characteristics when using virtual and physical arrays in multi-antenna channel characterisation. The authors quantify the frequency dependency of the channels in terms of their resilience to spatial fading and system capacity. The composite radiation pattern of the antenna and channel will impact the channel properties, the authors investigate these changes by measurement and analysis of channel data taken using both physical and virtual array configurations at the same locations. They find that at lower frequencies the resilience to spatial fading in LOS channels was less than half of the theoretic maximum. The difference in capacity and diversity gain between the LOS and NLOS channels was found to decrease with centre frequency. The different rates of increase result in a 4% average increase in capacity for a 500-MHz subband centred at 4.5 and 9.5 GHz for the LOS scenarios, whereas an increase of only 0.7% was experienced by the NLOS scenarios. In addition, this analysis indicates that the estimated diversity and capacity of multi-antenna channels decrease when using physical antenna arrays for measurements. - Author(s): H.M. Asif ; B. Honary ; H. Ahmed
- Source: IET Communications, Volume 6, Issue 10, p. 1195 –1204
- DOI: 10.1049/iet-com.2011.0265
- Type: Article
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In this work, the authors have developed a deterministic Ultra Wide Band (UWB) channel model for indoor environment using both ray-tracing technique and the art of computer game technology in 3D Game Studio (game development tool). In the developed model, the characteristics of indoor environment such as texture, transparency etc. can be taken into consideration while indoor parameters such as room size, objects position etc. can be interactively changed. Each time, indoor environment is changed, the program is compiled and hence, the underlying ray-tracing captures the updated indoor environment. It is the key novelty of the authors’ developed model and it has been so incorporated to make the authors’ model independent of any fixed (pre-defined) indoor environment. The developed model is compared against the standard statistical UWB channel model based on certain parameters such as delay spread etc. to address its validity and accuracy. The model is then enhanced to use multiple antennas on both sides of the system and capture the channel response accordingly. Finally, the developed model has been tested over a range of frequencies to see frequency effect on the channel impulse response. The simulation results have been presented and discussed in the simulation section.
Editorial: Ultra-wideband system design, signals and coding
Twenty years of ultrawideband: opportunities and challenges
Design of spectrally efficient ultra-wideband waveforms using Hermite–Rodriguez functions
Multi-tone frequency shift keying for ultrawideband wireless communications
Characterisation of ultra-wideband antenna arrays with spacings following a geometric progression
Ultra-wideband frequency dependency of capacity and diversity in multi-antenna indoor environments
Multiple-input multiple-output ultra-wide band channel modelling method based on ray tracing
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- Author(s): S. Bhatti ; S. Memon ; I.A. Jokhio ; M.A. Memon
- Source: IET Communications, Volume 6, Issue 10, p. 1205 –1211
- DOI: 10.1049/iet-com.2011.0246
- Type: Article
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To achieve precise modelling of real-time systems stochastic behaviours are considered which lead towards probabilistic modelling. Probabilistic modelling has been successfully employed in wide array of application domains including, for example, randomised distributed algorithms, communication, security and power management protocols. This study is an improvement over our previous work, which was based on the probabilistic analysis of a cluster-based fault tolerant target-tracking protocol (FTTT) using only grid-based sensor nodes arrangement. Probabilistic modelling is chosen for the analysis of FTTT protocol to facilitate benefits of symmetry reduction in conjunction with modelling. It is believed that for the first time correctness of the simplified version of a target-tracking protocol is verified by developing its continuous-time Markov chain (CTMC) model using symbolic modelling language. The proposed probabilistic model of a target-tracking wireless sensor networks will help to analyse the phases of FTTT protocol on a limited scale with finite utilisation of time. There are three main contributions of this study; first consideration of synchronised events between the modules, second, random placement of sensor nodes is taken into account in addition to grid-based sensor node arrangement, third one is the reduction in state space size through symmetry reduction technique, which also facilitates to analyse a larger size network. Symmetry reduction on Probabilistic Symbolic Model (PRISM) checker models is performed by PRISM-symm and the generic representatives in PRISM (GRIP) tool. Modelling of FTTT protocol is proved better with the usage of PRISM-symm after comparing the results of PRISM model, PRISM-symm and GRIP. - Author(s): E. Pasandshanjani and B.H. Khalaj
- Source: IET Communications, Volume 6, Issue 10, p. 1212 –1219
- DOI: 10.1049/iet-com.2011.0224
- Type: Article
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Underutilisation and scarcity of the available bandwidth have led to the idea of spectrum sharing as primary users partially transfer their rights for spectrum access to others in return for rewards. In this study, we introduce a new distributed game-theoretic approach in order to analyse the dynamic spectrum leasing problem in the uplink side of cellular cognitive radio networks. In such scenarios, it is necessary to define utility functions for primary and secondary users according to their incentives in order to model such interaction properly. We prove the existence of the Nash equilibrium point as well as its uniqueness for our model in the framework of standard power control algorithms and demonstrate fast convergence rate of the proposed method through numerical results. Owing to cellular architecture of the problem, the improvement in power consumption and signal-to-interference ratio (SIR) levels as users are given the opportunity to switch between different base stations is then investigated. Furthermore, we propose a simple admission control scheme and show the resulting performance improvement through simulations. In addition, the proposed framework provides the possibility of investigating trade-offs in terms of various system parameters. - Author(s): Y.S. Kavian ; A. Mahani ; H.F. Rashvand
- Source: IET Communications, Volume 6, Issue 10, p. 1220 –1228
- DOI: 10.1049/iet-com.2010.0895
- Type: Article
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In guaranteed-type applications the bandwidth planning and cost management are two important issues in deployment of optical core networks. A two-stage fuzzy-based approach is proposed for accommodating long-term demand uncertainties in dense wavelength division multiplexing optical networks. Here, the uncertainties are modelled using the Gaussian fuzzy membership functions. First, the forecasted part of demand matrix is introduced to Dijkstra shortest path-based routing algorithm. Then, the available wavelengths are assigned to demand uncertainties. Unlike existing algorithms, different bandwidth cost factors are assigned to the links of a lightpath according to network and links state information. The performance of proposed approach is evaluated on a typical optical link for uncertain traffic loads in Erlang mode. Simulation results show that the proposed fuzzy-based approach is up to 29% cost-effective for accommodating network demands in real-world applications comparing to existing algorithms. - Author(s): S. Linder ; P. Stenumgaard ; K. Wiklundh
- Source: IET Communications, Volume 6, Issue 10, p. 1229 –1233
- DOI: 10.1049/iet-com.2011.0125
- Type: Article
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The impulsiveness correction factor (ICF) has earlier been proposed as a simple measure for estimating the effect from pulsed interference on binary phase shift keying modulated digital radio systems. The advantage is that with the ICF, large errors introduced by the additive white Gaussian noise interference approximation can be reduced significantly, whereas the simplicity in interference analyses can be maintained. In this study, the ICF is further developed for other modulation schemes, such as M-phase shift keying and M-quadrature amplitude modulation and for a larger set of interference types. The results show that for one pulsed interference signal the ICF is suitable for all investigated modulation schemes. If the interference is a mixture of modulated and pulsed signals or several pulsed signals the authors suggest and evaluate ways to extend the ICF. - Author(s): F.S. Tabataba ; P. Sadeghi ; M.R. Pakravan
- Source: IET Communications, Volume 6, Issue 10, p. 1234 –1244
- DOI: 10.1049/iet-com.2011.0726
- Type: Article
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In this study, the authors optimise the outage probability of amplify and forward incremental relaying (IR) scheme using two different power allocation methods in the presence of channel estimation errors. The authors find the outage probability of IR scheme and minimise it subject to traditional power (TP) constraint in which the sum of nodes' powers is fixed and outage-dependent power (ODP) constraint which is compatible with the physical concept of IR and takes into account the quality of the direct path in the optimisation problem. The authors provide closed-form expressions to allocate power to pilot and data symbols of both the source and the relay. Although, their analysis uses high signal-to-noise-ratio (SNR) approximation, the analytical solutions perform very close to optimal ones obtained through global numerical search. The authors show that ODP constraint has substantial superiority over TP constraint, especially when the relay is placed close to the source. Moreover, the authors compare power-optimised IR subject to the mentioned power constraints with equal power allocation scheme and show the impact of power optimisation on the outage performance of IR system. - Author(s): J.J. Liu ; G. Wei ; Y.G. Wang
- Source: IET Communications, Volume 6, Issue 10, p. 1245 –1251
- DOI: 10.1049/iet-com.2010.0767
- Type: Article
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To balance the traffic in high-speed collaborative transmission, the static rate allocation problem over heterogeneous wireless access networks is formulated in a weighted bargaining game framework, where the heterogeneity of transmission capability of different networks is taken into account. The weights in the framework, which are used to describe the bargaining power of the bargaining game, are determined by the available bit rates of different networks. With the maximised throughput gain as the optimal objective, the closed form of the Nash bargaining solution is derived with the Lagrange multipliers method. Simulation results demonstrate that the presented framework is more efficient with completely balanced traffic so as to make full use of the heterogeneous network resource and prevent network saturation as much as possible. - Author(s): S. Aghajeri ; A. Reza Sharafat ; K. Navaie
- Source: IET Communications, Volume 6, Issue 10, p. 1252 –1261
- DOI: 10.1049/iet-com.2011.0476
- Type: Article
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In a dynamic spectrum sharing system, secondary users (SUs) attempt to maximise their throughput while preserving a given level of quality of service (QoS) for primary users (PUs). In doing so, the secondary network monitors the spectrum and decides on spectrum availability, which at times and for various reasons, may be erroneous. If spectrum is sensed as available, the secondary network selects an appropriate spectrum access strategy, and adjusts other communication parameters such as transmit power levels. In this study, the authors analyse primary service outage degradation caused by secondary access with non-ideal spectrum sensing. For different spectrum access strategies, namely, the overlay and the modified underlay spectrum access (MUSA), the authors derive a closed-form expression for the maximum outage probability degradation (MOD) in the presence of spectrum sensing errors and fading and show how adjustments by secondary service can result in attaining the desired QoS for PUs. Besides, for a given acceptable MOD in the primary network, the authors obtain a lower bound on the achievable expected rate of the secondary service in Nakagami-m and Rayleigh fading channels. Simulations confirm the analysis and show that MUSA considerably increases the secondary service rate, particularly when the activity of primary service is above 50%. - Author(s): M. Abusubaih
- Source: IET Communications, Volume 6, Issue 10, p. 1262 –1269
- DOI: 10.1049/iet-com.2011.0420
- Type: Article
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Packet loss in 802.11 WLANs (wireless local area networks) can occur either because of collision or a signal that is not strong enough at the receiver antenna. A challenging issue is the determination of packet loss cause once it occurs, which is a key for improving the performance of 802.11 WLANs. This article proposes and evaluates an algorithm to achieve this goal. The core of this algorithm is power level statistics at the receiver MAC. The algorithm learns from the received power levels of both correct and corrupted packets and decides whether a packet is lost because of collision or a weak signal. The results of extensive simulation experiments have shown that the proposed approach has a good potential for diagnosing the cause of packet losses in 802.11 WLANs. - Author(s): R.D. Joshi and P.P. Rege
- Source: IET Communications, Volume 6, Issue 10, p. 1270 –1277
- DOI: 10.1049/iet-com.2011.0257
- Type: Article
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Self-organising ad hoc networks need development of efficient routing protocols in terms of reliable routing and energy conservation. For dense ad hoc networks, optimised link state routing (OLSR) protocol is suitable owing to its multi-point relaying (MPR) feature. The authors have tried to make OLSR energy efficient by making effective neighbour selection based on residual battery energy of a node and traffic conditions that influence the drain rate of the node in the network. The authors have considered the multipath and source routing concept for route selection and a route recovery technique to tackle mobility issue efficiently. With these modifications the protocol becomes energy efficient and at the same time achieves balancing of network load. Simulation results of OLSR and the modified protocol OLSRM, show improvement in ‘Number of nodes alive’ against variation in pause time, speed and node density. In this study, the authors have tried to model the network behaviour using R software. The work also describes analytical modelling of the protocol performance in terms of energy aware metric, ‘Number of nodes alive’ with respect to simulation time as a common frame of reference. Using analytical modelling approach the authors can predict correct network behaviour for future instances. - Author(s): A. Wagemakers ; F.J. Escribano ; L. López ; M.A.F. Sanjuán
- Source: IET Communications, Volume 6, Issue 10, p. 1278 –1283
- DOI: 10.1049/iet-com.2011.0865
- Type: Article
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Recent work has shown that chaos-based communication systems can yield performances as good as their non-chaotic counterparts in additive white Gaussian noise (AWGN), and behave even better in flat-fading channels. However, much of this work relies on computer simulations and there is still a need to study in depth the implementation issues of such systems. The authors address for the first time a fixed-point arithmetic implementation of the iterative decoding algorithm for a recently proposed and successful class of parallel concatenated chaos-based coded modulations. The novel digital signal processor (DSP) results demonstrate that it is possible to implement in standard hardware competitive chaos-based communication systems. - Author(s): K. Chung
- Source: IET Communications, Volume 6, Issue 10, p. 1284 –1290
- DOI: 10.1049/iet-com.2011.0894
- Type: Article
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The study introduces novel codes called irregular repeat quaternary-accumulate (IRqA) codes whose performance is better than that of the standard irregular repeat accumulate (IRA) codes for the medium-to-short block lengths. The codes are a serial concatenation of an irregular repeat code and a quaternary-accumulate (qA) code. The decoding is performed iteratively by exchanging extrinsic information. The decoding of qA codes is executed using two-dimensional BCJR (Bahl, Cocke, Jelinek and Raviv) decoding. Our codes are found by optimising irregular repetition factors, based on EXIT charts. We also present some simulation results, which show that IRqA codes surpass IRA codes with the comparable encoding and decoding complexities. - Author(s): H.-Y. Lu and H.-S. Hung
- Source: IET Communications, Volume 6, Issue 10, p. 1291 –1299
- DOI: 10.1049/iet-com.2011.0294
- Type: Article
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In this study, the authors present a particle swarm optimisation (PSO) scheme for the joint issue of antenna combing (AC) and power allocation in order to concurrently enhance throughput and reduce hardware cost for multiple-input multiple-output cooperative systems. In the proposed scheme, each particle's position is characterised by three matrices: the receive AC matrix of the cooperative relay; the receive AC matrix of the destination node; and the power allocation matrix of the cooperative relay. Based on the constrained maximisation of mutual information, the proposed scheme carries out the PSO's iterative update mechanisms to concurrently refine the position of each particle until the largest mutual information is attained. Simulation results show that the proposed scheme is guaranteed to converge, outperforms existing schemes of antenna selection or power allocation at the price of higher computational load and achieves near-optimal capacity of the benchmark (full radio frequency (RF) chains) scheme at a significant saving of RF chains. - Author(s): W. Gappmair
- Source: IET Communications, Volume 6, Issue 10, p. 1300 –1305
- DOI: 10.1049/iet-com.2011.0545
- Type: Article
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In a recent study, the error performance of pulse-position modulation (PPM) schemes has been investigated for a terrestrial free-space optical (FSO) link, which was assumed to be impaired by both turbulent atmosphere and pointing errors. Only for the binary case a closed-form solution was achievable, whereas for non-binary conditions just an approximate relationship could be given. The key point in this respect was the approximation of the complementary error function so that the two-fold integral, otherwise required in this context, ended up in a closed form. In the current contribution, the problem is tackled by an additive combination of exponentials whose coefficients are optimised in the least-square sense. It turns out that second-order approximations are a good compromise between accuracy and computational complexity. - Author(s): B. König ; J.M. Alcaraz Calero ; J. Kirschnick
- Source: IET Communications, Volume 6, Issue 10, p. 1306 –1315
- DOI: 10.1049/iet-com.2011.0200
- Type: Article
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This study presents a scalable and elastic distributed system for monitoring cloud infrastructure based on a pure peer-to-peer architecture. Its distributed nature enables deploying long-living queries across the network to monitor a diverse set of entities and metrics, spanning across all layers of a cloud stack that can change rapidly. This allows for aggregating low-level metrics from operating systems, to higher-level application-specific metrics derived from services, databases or application log files. The observed metrics and information can be evaluated and used to reliably trigger policies to automate complex management tasks within a cloud environment. The architecture incorporates a query framework for obtaining high-level information and a policy framework to provide self-management capabilities to monitored cloud infrastructure. The system has been implemented as a proof of concept. Details and statistical results are provided to validate the scalability of the underlying architecture. - Author(s): W. Nurmi and S. Nooshabadi
- Source: IET Communications, Volume 6, Issue 10, p. 1316 –1325
- DOI: 10.1049/iet-com.2010.1124
- Type: Article
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Multiple input multiple output (MIMO) techniques are widely employed in modern wireless systems. The most prominent approaches to MIMO communication are space–time coding (STC) and spatial multiplexing (SM). Less studied is a hybrid technique called adaptive MIMO switching (AMS), which may be employed by fixing the transmission rate and selecting between space–time block coding and SM transmission modes based on instantaneous channel conditions to achieve the most efficient link. This study presents a hardware implementations of a selector algorithm and a detector employing it. The detector is designed for a 2×2 MIMO system and was implemented on an Altera Cyclone II FPGA. In addition, two transmission protocols with decision feedback from the receiver to the transmitter via a low-rate feedback channel are introduced and the feasibility of switching for high-data-rate transmissions is discussed. - Author(s): H.-P. Lee ; H.-C. Chang ; T.-K. Truong
- Source: IET Communications, Volume 6, Issue 10, p. 1326 –1333
- DOI: 10.1049/iet-com.2011.0748
- Type: Article
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In this study, an efficient and fast algebraic decoding algorithm (ADA) for the binary systematic quadratic residue (QR) code of length 73 with the reducible generator polynomial to correct up to six errors is proposed. The S(I, J) matrix method given by He et al. (2001) is utilised to compute the unknown syndromes S5. A technique called swap base is proposed to correct the weight-4 error patterns. To correct the weight-5 error patterns, the new error-locator polynomials for decoding the five errors are derived. Finally, the modified shift-search algorithm (SSA) developed by Lin et al. (2010) is applied to correct the weight-6 error patterns. Moreover, the computations of all syndromes are achieved in a small finite field. Simulation results show that the proposed ADA is practical. - Author(s): B.A. Angélico ; P.J.E. Jeszensky ; T. Abrão
- Source: IET Communications, Volume 6, Issue 10, p. 1334 –1339
- DOI: 10.1049/iet-com.2011.0012
- Type: Article
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The study proposes a constrained least square (CLS) pre-distortion scheme for multiple-input single-output (MISO) multiple access ultra-wideband (UWB) systems. In such a scheme, a simple objective function is defined, which can be efficiently solved by a gradient-based algorithm. For the performance evaluation, scenarios CM1 and CM3 of the IEEE 802.15.3a channel model are considered. Results show that the CLS algorithm has a fast convergence and a good trade-off between intersymbol interference (ISI) and multiple access interference (MAI) reduction and signal-to-noise ratio (SNR) preservation, performing better than time-reversal (TR) pre-distortion.
Modelling and symmetry reduction of a target-tracking protocol using wireless sensor networks
Primary–secondary interaction modelling in cellular cognitive radio networks: a game-theoretic approach
Two-stage uncertainty incorporating in optical core networks
Extension of the impulsiveness correction factor for several modulation schemes and various interfering signals for interference control in dynamic wireless applications
Outage-dependent and traditional power optimisations for amplify and forward incremental relaying with channel estimation errors
Game-theoretic rate allocation with balanced traffic in collaborative transmission over heterogeneous wireless access networks
Primary service outage degradation in dynamic spectrum sharing with non-ideal spectrum sensing
Approach for discriminating losses in 802.11 wireless LANs
Implementation and analytical modelling of modified optimised link state routing protocol for network lifetime improvement
Competitive decoders for turbo-like chaos-based systems
Irregular repeat quaternary-accumulate (IRqA) codes and two-dimensional BCJR decoding
Antenna combining and power allocation-assisted multiple-input multiple-output cooperative communications: a joint approach
Novel results on pulse-position modulation performance for terrestrial free-space optical links impaired by turbulent atmosphere and pointing errors
Elastic monitoring framework for cloud infrastructures
Very-large-scale integration hardware implementation of adaptive space–time coding/spatial multiplexing switching
Algebraic decoding of the (73, 37, 13) quadratic residue code
Constrained least square pre-distortion scheme for multiuser ultra-wideband
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