Dr Fabien Heliot
Research Assistant
Qualifications: Msc, PhD, MIEEE
Email: f.heliot@surrey.ac.uk
Phone: Work: 01483 68 9492
Room no: 39 BA 01
Further information
Biography
Fabien Héliot (S'05-M'07) received the M.Sc. degree in Telecommunications from the Institut Sup\'erieur de l'Electronique et du Numérique (ISEN), Toulon, France, and the Ph.D. degree in Mobile Telecommunications from King's College London, in 2002 and 006, respectively. He is currently a research fellow at the Centre for Communication Systems Research (CCSR) of the University of Surrey. He has been actively involved in European Commission funded projects such as IST FIREWORKS and IST ROCKET projects, and more recently in the award-winning project ICT EARTH project, a leading European project investigating the energy efficiency of mobile communication systems.
Research Interests
His current interests are:
- Energy efficiency-spectral efficiency fundamental trade-off;
- Cooperative communication;
- Multi-cell system;
- Resource optimisation problem.
His broader interests are
- MIMO / Precoding;
- Space-time / lattice coding;
- Ultra Wide-Band.
Publications
Highlights
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(2012) 'On the energy efficiency-spectral efficiency trade-off over the MIMO rayleigh fading channel'. IEEE Transactions on Communications, 60 (5), pp. 1345-1356.Full text is available at: http://epubs.surrey.ac.uk/634484/
Abstract
Along with spectral efficiency (SE), energy efficiency (EE) is becoming one of the key performance evaluation criteria for communication system. These two criteria, which are conflicting, can be linked through their trade-off. The EE-SE trade-off for the multi-input multi-output (MIMO) Rayleigh fading channel has been accurately approximated in the past but only in the low-SE regime. In this paper, we propose a novel and more generic closed-form approximation of this trade-off which exhibits a greater accuracy for a wider range of SE values and antenna configurations. Our expression has been here utilized for assessing analytically the EE gain of MIMO over single-input single-output (SISO) system for two different types of power consumption models (PCMs): the theoretical PCM, where only the transmit power is considered as consumed power; and a more realistic PCM accounting for the fixed consumed power and amplifier inefficiency. Our analysis unfolds the large mismatch between theoretical and practical MIMO vs. SISO EE gains; the EE gain increases both with the SE and the number of antennas in theory, which indicates that MIMO is a promising EE enabler; whereas it remains small and decreases with the number of transmit antennas when a realistic PCM is considered. © 2012 IEEE.
- .
(2012) 'On the Energy Efficiency-Spectral Efficiency Trade-Off in the Uplink of CoMP System'. IEEE IEEE Transactions on Wireless Communications, 11 (2), pp. 556-561.Full text is available at: http://epubs.surrey.ac.uk/244021/
Abstract
In this paper, we derive a generic closed-form approximation (CFA) of the energy efficiency-spectral efficiency (EE-SE) trade-off for the uplink of coordinated multi-point (CoMP) system and demonstrate its accuracy for both idealistic and realistic power consumption models (PCMs). We utilize our CFA to compare CoMP against conventional non-cooperative system with orthogonal multiple access. In the idealistic PCM, CoMP is more energy efficient than non-cooperative system due to a reduction in power consumption; whereas in the realistic PCM, CoMP can also be more energy efficient but due to an improvement in SE and mainly for cell-edge communication and small cell deployment.
- . (2011) 'An accurate closed-form approximation of the distributed MIMO outage probability'. IEEE Transactions on Wireless Communications, 10 (1), pp. 5-11.
- .
(2008) 'An accurate closed-form approximation of the average probability of error over a log-normal fading channel'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 7 (5), pp. 1495-1500.Full text is available at: http://epubs.surrey.ac.uk/2591/
Journal articles
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(2012) 'Energy Efficiency Contours for Broadcast Channels
Using Realistic Power Models'. IEEE Transactions on Wireless Communications, 11 (11), pp. 4017-4025.Full text is available at: http://epubs.surrey.ac.uk/725969/
Abstract
Energy savings are becoming a global trend, hence the importance of energy efficiency (EE) as an alternative performance evaluation metric. This paper proposes an EE based resource allocation method for the broadcast channel (BC), where a linear power model is used to characterize the power consumed at the base station (BS). Having formulated our EE based optimization problem and objective function, we utilize standard convex optimization techniques to show the concavity of the latter, and thus, the existence of a unique globally optimal energy-efficient rate and power allocation. Our EE based resource allocation framework is also extended to incorporate fairness, and provide a minimum user satisfaction in terms of spectral efficiency (SE). We then derive the generic equation of the EE contours and use them to get insights about the EE-SE trade-off over the BC. The performances of the aforementioned resource allocation schemes are compared for different metrics against the number of users and cell radius. Results indicate that the highest EE improvement is achieved by using the unconstrained optimization scheme, which is obtained by significantly reducing the total transmit power. Moreover, the network EE is shown to increase with the number of users and decrease as the cell radius increases.
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(2012) 'Energy-efficient Power Allocation for Point-to-point MIMO Systems over the Rayleigh Fading Channel'. IEEE Wireless Communications Letters, 1 (4), pp. 304-307.Full text is available at: http://epubs.surrey.ac.uk/726075/
Abstract
It is well-established that transmitting at full power is the most spectral-efficient power allocation strategy for pointto- point (P2P) multi-input multi-output (MIMO) systems, however, can this strategy be energy efficient as well? In this letter, we address the most energy-efficient power allocation policy for symmetric P2P MIMO systems by accurately approximating in closed-form their optimal transmit power when a realistic MIMO power consumption model is considered. In most cases, being energy efficient implies a reduction in transmit and overall consumed powers at the expense of a lower spectral efficiency.
- .
(2012) 'A Very Tight Approximation of the SISO Energy Efficiency-Spectral Efficiency Trade-Off'. IEEE IEEE Communications Letters, 16 (6), pp. 850-853.Full text is available at: http://epubs.surrey.ac.uk/710806/
Abstract
Beside the well-established spectral-efficiency (SE), energy-efficiency (EE) is currently becoming an important performance evaluation metric, which in turn makes the EE-SE trade-off as a prominent criterion for efficiently designing future communication systems. In this letter, we propose a very tight closed-form approximation (CFA) of this trade-off over the single-input single-output (SISO) Rayleigh flat fading channel. We first derive an improved approximation of the SISO ergodic capacity by means of a parametric function and then utilize it for obtaining our novel EE-SE trade-off CFA, which is also generalized for the symmetric multi-input multi-output channel. We compare our CFA with existing CFAs and show its improved accuracy in comparison with the latter.
- .
(2012) 'On the energy efficiency-spectral efficiency trade-off over the MIMO rayleigh fading channel'. IEEE Transactions on Communications, 60 (5), pp. 1345-1356.Full text is available at: http://epubs.surrey.ac.uk/634484/
Abstract
Along with spectral efficiency (SE), energy efficiency (EE) is becoming one of the key performance evaluation criteria for communication system. These two criteria, which are conflicting, can be linked through their trade-off. The EE-SE trade-off for the multi-input multi-output (MIMO) Rayleigh fading channel has been accurately approximated in the past but only in the low-SE regime. In this paper, we propose a novel and more generic closed-form approximation of this trade-off which exhibits a greater accuracy for a wider range of SE values and antenna configurations. Our expression has been here utilized for assessing analytically the EE gain of MIMO over single-input single-output (SISO) system for two different types of power consumption models (PCMs): the theoretical PCM, where only the transmit power is considered as consumed power; and a more realistic PCM accounting for the fixed consumed power and amplifier inefficiency. Our analysis unfolds the large mismatch between theoretical and practical MIMO vs. SISO EE gains; the EE gain increases both with the SE and the number of antennas in theory, which indicates that MIMO is a promising EE enabler; whereas it remains small and decreases with the number of transmit antennas when a realistic PCM is considered. © 2012 IEEE.
- .
(2012) 'On the Energy Efficiency-Spectral Efficiency Trade-Off in the Uplink of CoMP System'. IEEE IEEE Transactions on Wireless Communications, 11 (2), pp. 556-561.Full text is available at: http://epubs.surrey.ac.uk/244021/
Abstract
In this paper, we derive a generic closed-form approximation (CFA) of the energy efficiency-spectral efficiency (EE-SE) trade-off for the uplink of coordinated multi-point (CoMP) system and demonstrate its accuracy for both idealistic and realistic power consumption models (PCMs). We utilize our CFA to compare CoMP against conventional non-cooperative system with orthogonal multiple access. In the idealistic PCM, CoMP is more energy efficient than non-cooperative system due to a reduction in power consumption; whereas in the realistic PCM, CoMP can also be more energy efficient but due to an improvement in SE and mainly for cell-edge communication and small cell deployment.
- . (2011) 'An accurate closed-form approximation of the distributed MIMO outage probability'. IEEE Transactions on Wireless Communications, 10 (1), pp. 5-11.
- .
(2009) 'A Tight Closed-Form Approximation of the Log-Normal Fading Channel Capacity'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 8 (6), pp. 2842-2847.Full text is available at: http://epubs.surrey.ac.uk/2619/
- .
(2008) 'An accurate closed-form approximation of the average probability of error over a log-normal fading channel'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 7 (5), pp. 1495-1500.Full text is available at: http://epubs.surrey.ac.uk/2591/
- .
(2006) 'Design and performance analysis of a space-time block coding scheme for single band UWB'. INST ENGINEERING TECHNOLOGY-IET IEE PROCEEDINGS-COMMUNICATIONS, 153 (1), pp. 127-135.Full text is available at: http://epubs.surrey.ac.uk/2614/
- . (2005) 'Concatenated space-time trellis codes with optimal puncturing patterns'. IEE-INST ELEC ENG IEE PROCEEDINGS-COMMUNICATIONS, 152 (4), pp. 385-392.
- . (2004) 'Search for space - time trellis codes: novel codes for Rayleigh fading channels'. IEE-INST ELEC ENG IEE PROCEEDINGS-COMMUNICATIONS, 151 (1), pp. 25-31.
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(2003) '4-PSK space-time trellis codes with five and six transmit antennas for slow Rayleigh fading channels'. IEE-INST ELEC ENG ELECTRONICS LETTERS, 39 (3), pp. 297-299.doi: 10.1049/el:20030220
Conference papers
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(2012) 'On the Energy Efficiency-Spectral Efficiency Trade-Off of the 2BS-DMIMO System'. Quebec city, Canada: IEEE VTC-FallFull text is available at: http://epubs.surrey.ac.uk/726372/
Abstract
In this paper, we propose a novel closed-form approximation of the Energy Efficiency vs. Spectral Efficiency (EESE) trade-off for the uplink/downlink of distributed multipleinput multiple-output (DMIMO) system with two cooperating base stations. Our closed-form expression can be utilized for evaluating the idealistic and realistic EE-SE performances of various antenna configurations as well as assessing how DMIMO compares against MIMO system in terms of EE. Results show a tight match between our closed-form approximation and the Monte-Carlo simulation for both idealistic and realistic EESE trade-off. Our results also show that given a target SE requirement, there exists an optimal antenna setting that maximizes the EE. In addition, DMIMO scheme can offer significant improvement in terms of EE over the MIMO scheme.
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(2012) 'Energy-Efficiency based Resource Allocation for
the Orthogonal Multi-user Channel'. Quebec city, Canada: IEEE VTC-fallFull text is available at: http://epubs.surrey.ac.uk/726367/
Abstract
Energy efficiency (EE) is emerging as a key design criterion for both power limited applications, i.e. mobile devices, and power-unlimited applications, i.e. cellular network. Whereas, resource allocation is a well-known technique for improving the performance of communication system. In this paper, we design a simple and optimal EE-based resource allocation method for the orthogonal multi-user channel by adapting the transmit power and rate to the channel condition such that the energy-per-bit consumption is minimized. We present our EE framework, i.e. EE metric and node power consumption model, and utilizes it for formulating our EE-based optimization problem with or without constraint. In both cases, we derive explicit formulations of the optimal energy-per-bit consumption as well as optimal power and rate for each user. Our results indicate that EE-based allocation can substantially reduce the consumed power and increase the EE in comparison with spectral efficiency-based allocation.
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(2012) 'A Tight Closed-Form Approximation of the SISO Energy Efficiency-Spectral Efficiency Trade-Off'. Berlin, Germany: ICT Future & Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/726078/
Abstract
Due to the rise of the energy efficiency (EE) as a system performance evaluation criterion, the EE-spectral efficiency (SE) trade-off is becoming a key tool for getting insight on how to efficiently design future communication system. As far as the single-input single-output (SISO) Rayleigh fading channel is concerned, the EE-SE trade-off has been accurately approximated in the past but only at low-SE. In this paper, we propose a novel and more generic closed-form approximation (CFA) of this EE-SE trade-off which is very accurate for any SE values. We compare our CFA with two existing CFAs and show the great accuracy of the former for a wider range of SE in comparison with the latter. As an application, we use our CFA to study the variation of EE-SE trade-off when a realistic power model is assumed and to compare the energy consumption of SISO against a 2x2 multi-input multi-output (MIMO) system over the Rayleigh fading channel.
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(2012) 'Energy-efficiency based resource allocation for the scalar broadcast channel'. IEEE IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference, WCNC, pp. 193-197.Full text is available at: http://epubs.surrey.ac.uk/726076/
Abstract
Until recently, link adaptation and resource allocation for communication system relied extensively on the spectral efficiency as an optimization criterion. With the emergence of the energy efficiency (EE) as a key system design criterion, resource allocation based on EE is becoming of great interest. In this paper, we propose an optimal EE-based resource allocation method for the scalar broadcast channel (BC-S). We introduce our EE framework, which includes an EE metric as well as a realistic power consumption model for the base station, and utilize this framework for formulating our EE-based optimization problem subject to a power as well as fairness constraints. We then prove the convexity of this problem and compare our EE-based resource allocation method against two other methods, i.e. one based on sum-rate and one based on fairness optimization. Results indicate that our method provides large EE improvement in comparison with the two other methods by significantly reducing the total consumed power. Moreover, they show that near-optimal EE and average fairness can be simultaneously achieved over the BC-S channel. © 2012 IEEE.
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(2012) 'A low-complexity precoding scheme for the downlink of multi-cell multi-user MIMO AF system'. IEEE Wireless Communications and Networking Conference, WCNC, , pp. 737-741.Full text is available at: http://epubs.surrey.ac.uk/726077/
Abstract
Because of its simplicity, amplify-and-forward (AF) is one of the most popular cooperative relaying technique. Relays are used in cooperative communication to improve reliability, coverage or spectral efficiency of cell-edge users. However, relays tend to increase the interferences seen by users of adjacent cells, particularly by the cell-edge users, when used in multi-cell systems. In this paper, we propose a low-complexity precoding scheme to mitigate the effect of other-cell interference (OCI) in cooperative communication. The scheme is designed by taking into account the interference plus noise covariance matrix of each user for mitigating the interference at each receiver by means of precoding at the relay node. Simulation results show the effectiveness of the proposed scheme, both in terms of sum-rate and computational complexity, when compared to other existing OCI-aware precoding algorithms for AF. © 2012 IEEE.
- . (2012) 'An interference-aware precoding scheme for the downlink of multi-cell multi-user MIMO communication'. Proceedings of the 2012 IEEE 4th International Conference on Adaptive Science and Technology, ICAST 2012, , pp. 29-32.
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(2011) 'Trade-off between Energy Efficiency and Spectral
Efficiency in the Uplink of a Linear Cellular
System with Uniformly Distributed User Terminals'. IEEE Proc. IEEE PIMRC, Toronto, Canada: IEEE PIMRC, pp. 2407-2407.Full text is available at: http://epubs.surrey.ac.uk/534278/
Abstract
In this paper, we propose a tight closed-form approximation of the Energy Efficiency vs. Spectral Efficiency (EE-SE) trade-off for the uplink of a linear cellular communication system with base station cooperation and uniformly distributed user terminals. We utilize the doubly-regular property of the channel to obtain a closed form approximation using the Marˇcenko Pasture law. We demonstrate the accuracy of our expression by comparing it with Monte-Carlo simulation and the EE-SE trade-off expression based on low-power approximation. Results show the great tightness of our expression with Monte-Carlo simulation.We utilize our closed form expression for assessing the EE performance of cooperation for both theoretical and realistic power models. The theoretical power model includes only the transmit power, whereas the realistic power model incorporates the backhaul and signal processing power in addition to the transmit power. Results indicate that for both power models, increasing the number of antennas leads to an improvement in EE performance, whereas, increasing the number of cooperating BSs results in a loss in EE when considering the realistic power model.
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(2011) 'Energy Efficiency Analysis of In-Building MIMO
AF Communication'. IEEE IEEE International Wireless Communicatins and Mobile Computing (IWCMC-2011), Istanbul, Turkey: IEEE International Wireless Communicatins and Mobile Computing (IWCMC-2011), pp. 912-917.Full text is available at: http://epubs.surrey.ac.uk/7065/
Abstract
Cooperative communication is an effective approach for increasing the spectral efficiency and/or the coverage of cellular networks as well as reducing the cost of network deployment. However, it remains to be seen how energy efficient it is. In this paper, we assess the energy efficiency of the conventional Amplify-and- forward (AF) scheme in an in-building relaying scenario. This scenario simplifies the mutual information formulation of the AF system and allows us to express its channel capacity with a simple and accurate closed-form approximation. In addition, a framework for the energy efficiency analysis of AF system is introduced, which includes a power consumption model and an energy efficiency metric, i.e. the bit-per-joule capacity. This framework along with our closed-form approximation are utilized for assessing both the channel and bit-per-joule capacities of the AF system in an in-building scenario. Our results indicate that transmitting with maximum power is not energy efficient and that AF system is more energy efficient than point-to-point communication at low transmit powers and signal-to-noise ratios.
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(2011) 'An accurate closed-form approximation of the energy efficiency-spectral efficiency trade-off over the MIMO Rayleigh fading channel'. IEEE International Conference on Communications, Kyoto, Japan: IEEE ICC'11, pp. 1-6.Full text is available at: http://epubs.surrey.ac.uk/725966/
Abstract
Energy efficiency (EE) is gradually becoming one of the key criteria, along with the spectral efficiency (SE), for evaluating communication system performances. However, minimizing the EE while maximizing the SE are conflicting objectives and, thus, the main criterion for designing efficient communication systems will become the trade-off between SE and EE. The EE-SE trade-off for the multi-input multi-output (MIMO) Rayleigh fading channel has been accurately approximated in the past but only in the low-SE regime. In this paper, we propose a novel and more generic closed-form approximation of this EE-SE trade-off which exhibits a greater accuracy for a wider range of SE values and antenna configurations. Our expression, which can easily be used for evaluating and comparing the EE-SE trade-off of MIMO communication system, has been utilized in this paper for analyzing the impact of using multiple antennas on the EE and the EE gain of MIMO in comparison with single-input single-output (SISO) system. Our results indicate that EE can be improved predominantly through receive diversity in the low-SE regime and that MIMO is far more energy efficient than SISO at high SE over the Rayleigh fading channel.
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(2011) 'On Achievable Rate Region of Multiple Coordinated Multiple Access Channels'. IEEE 73rd IEEE Vehicular technology Conference, Budapest, Hungary: IEEE VTC-springFull text is available at: http://epubs.surrey.ac.uk/725965/
Abstract
Coordination between two or more multiple access channel (MAC) receivers can enlarge the achievable rate region of the whole system. This paper focuses on coordination by sharing the codebooks of the users between the receivers of MACs. We first define the achievable rate region of the time invariant multiple coordinated MAC (MCMAC) and subsequently derive its achievable rate region. We later express the achievable rate region in terms of the dominating points. We base our numerical analysis on the two-user two-receiver Gaussian coordinated MAC and make comparison with the interference channel, full cooperation and the individual MAC performance analysis. It is observed that this approach though suboptimal is less complex in comparison with full cooperation and that the MCMAC rate region is at least equal to the rate region of the uncoordinated approach. Over several channel states, the rate region of MCMAC exceeds that of the uncoordinated approach.
- . (2011) 'On the Energy Efficiency Gain of MIMO Communication under Various Power Consumption Models'. Warsaw, Poland: Future Network and Mobile Summit
- . (2011) 'Other-cell interference aware precoding for the downlink of multi-user MIMO AF communication'. IEEE Vehicular Technology Conference, Budapest, Hungary: IEEE VTC-spring
- . (2011) 'Codebook-based precoding and power allocation for nonregenerative dual hop relay systems'. IEEE Vehicular Technology Conference, Budapest, Hungary: IEEE VTC-spring
- . (2011) 'Energy Efficiency Analysis of Idealized Coordinated Multi-Point Communication System'. IEEE Vehicular technology Conference, Budapest, Hungary: IEEE VTC-spring
- . (2011) 'Closed-form Approximation for the Trade-off between Energy Efficiency and Spectral Efficiency in the Uplink of Cellular Network'. Vienna, Austria: European Wireless Conference
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(2010) 'Power Allocation for the Downlink of Nonregenerative Cooperative Multi-User MIMO Communication system'. Proc. IEEE PIMRC, Istanbul, Turkey: IEEE PIMRCFull text is available at: http://epubs.surrey.ac.uk/2667/
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(2010) 'On the spectral efficiency maximization of Nonregenerative Cooperative MIMO Communication Systems'. Proc. IEEE PIMRC, Istanbul, Turkey: IEEE PIMRCFull text is available at: http://epubs.surrey.ac.uk/2666/
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(2010) 'Low-Complexity Power Allocation Schemes for the Downlink of Nonregenerative Cooperative Multi-User MIMO Communication System'. Proc. ICT Future Network & Mobile Summit, Florence, Italy: ICT Future Network & Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2662/
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(2010) 'Weighted Sum-Rate based Power Allocation for the Uplink of Nonregenerative Cooperative Multi-User MIMO Communication System'. Proc. ICT Future Network & Mobile Summit, Florence, Italy: ICT Future Network & Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2661/
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(2009) 'A Closed-Form Approximation of the Outage Probability for Distributed MIMO Systems'. Proc. IEEE SPAWC, Perugia, Italy: IEEE SPAWC'09Full text is available at: http://epubs.surrey.ac.uk/2623/
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(2009) 'Receive Knowledge Only Power Allocation for Nonregenerative Cooperative MIMO Communication'. Proc. IEEE SPAWC, Perugia, Italy: IEEE SPAWC'09Full text is available at: http://epubs.surrey.ac.uk/2624/
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(2009) 'An Asymptotical Approximation of Outage Probability for Distributed MIMO Systems'. Proc. ICT Mobile Summit, Santander, Spain: ICT Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2660/
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(2009) 'Power Allocation for Nonregenerative Cooperative MIMO Communication under Various Levels of Channel State Information'. Proc. ICT Mobile Summit, Santander, Spain: ICT Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2659/
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(2009) 'A Novel Multi-layer Cooperative Decode and Forward Scheme'. IEEE 2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, Barcelona, SPAIN: 69th IEEE Vehicular Technology Conference, pp. 1248-+.Full text is available at: http://epubs.surrey.ac.uk/2625/
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(2008) 'An Accurate Closed-Form Approximation of the Ergodic Capacity over Log-Normal Fading Channels'. IEEE 2008 IEEE 19TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS, Cannes, FRANCE: 19th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, pp. 88-92.Full text is available at: http://epubs.surrey.ac.uk/2628/
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(2008) 'A Generalised Low-Complexity SISO Sphere Decoder for Lattice-based Communication Systems'. Proc. ICT Mobile Summit, Stockholm, Sweden: ICT Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2655/
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(2008) 'A Low-Complexity Transmit Cooperation Scheme based on Layered Higher Order Modulation'. Proc. ICT Mobile Summit, Stockholm, Sweden: ICT Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2656/
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(2008) 'On the Performance of Algebraic STBCs in WiMax Systems'. Proc. ICT Mobile Summit, Stockholm, Sweden: ICT Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2654/
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(2008) 'Link Performance Model for Multihop WiMax OFDMA Systems'. Proc. ICT Mobile Summit, Stockholm, Sweden: ICT Mobile SummitFull text is available at: http://epubs.surrey.ac.uk/2657/
- . (2005) 'Space-Time Trellis Coding Schemes for Single Band Ultra Wideband'. Aalborg, Denmark : Proc. Keio University - Aalborg University Joint Workshop for Broadband Wireless Communications,
- .
(2004) 'Performance of space-time block coding and space-time trellis coding for impulse radio'. IEEE GLOBECOM '04: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6, Dallas, TX: IEEE Global Telecommunications Conference (GLOBECOM 04), pp. 3225-3229.Full text is available at: http://epubs.surrey.ac.uk/2626/
- . (2004) 'Space-Time Coding for Ultra-Wide Bandwidth Signal'. London, UK : Proc. IEE seminar on UWB Communications,
- . (2003) 'Space-Time Block Coding with Orthogonal Pulses for Impulse Radio'. Yokosuka, Japan : Proc. 6th International Symposium on WPMC, , pp. 517-521-517-521.
- . (2003) 'Space-Time Coding for UWB'. Prague, Czech Rep. : Proc. COST 273,
- . (2003) '8-PSK and 16-QAM Space-Time Trellis Codes for Rayleigh Fading Channels with 2, 3 and 4 Transmit Antennas'. Aveiro, Portugal : Proc. IST Mobile Summit,
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(2003) 'Fast search techniques for obtaining space-time trellis codes for Rayleigh fading channels and its performance in CDMA systems'. IEEE 57TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, VTC 2003-SPRING, VOLS 1-4, PROCEEDINGS, Cheju Isl, SOUTH KOREA: 57th IEEE Vehicular Technology Conference, pp. 66-69.Full text is available at: http://epubs.surrey.ac.uk/2627/
- . (2003) 'Performance Characteristics of Novel 4-PSK Space-Time Trellis Codes in Fast Rayleigh Fading Channels'. Barcelona, Spain : Proc. COST 273,
Book chapters
- . (2012) 'Green Relay Techniques in Cellular Systems'. in Yu FR, Leung VCM, Zhang X (eds.) Green Communications and Networking CRC Press
- . (2012) 'On the Energy Efficiency-Spectral Efficiency Trade-off in Cellular Systems'. in Wu J, Sundeep R, Honggang Z (eds.) Green Communications: Theoretical Fundamentals, Algorithms and Applications CRC Press
- . (2012) 'On the Energy Efficiency-Spectral Efficiency Trade-off in Cellular Systems'. in Wu J, Rangan S, Zhang H (eds.) Green Communications CRC Press
Theses and dissertations
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(2006) Design and analysis of space-time block and trellis coding schemes for single-band UWB communications systems. King's College London, University of LondonFull text is available at: http://epubs.surrey.ac.uk/2588/
Abstract
Ultra Wide-Band (UWB) technology has recently attracted much research interest due to its appealing features in short-range mobile communications. These features include high-data rates, low power consumption, multiple-access communications and precise positioning capabilities. Space-Time Coding (STC) techniques, such as block coding and trellis coding, are known to be simple and practical ways to increase both the spectral efficiency and the capacity in wireless communications. The the- sis aims at designing robust and efficient space-time coding schemes well adapted to single-band UWB signalling. Thus, this work incorporates a fine analysis of a stan- dard Single Input Single Output (SISO) single-band UWB system, scrutinising every important aspect of this system including transceiver structure, channel modelling, multiple-access techniques and detection process. Research also leads to the deriva- tion of a novel closed-form approximation for the average probability of bit-error for single-band UWB systems. This in-depth study highlights drawbacks inherent to UWB systems such as time-jitter effects or rake-receiver complexity and proposes schemes that benefit from spatial diversity to mitigate these problems. Thus, the thesis concentrates on the design of new multiple-antenna space-time coding systems tailored for UWB communications. As a result, this work derives and generates gen- eralised full-rate space-time block codes based on orthogonal pulses to capture both spatial and multipath diversities. Space-time trellis coded modulation is then revis- ited to further improve the spectral efficiency limit and to deliver the high-data rates promised by UWB technology. A new version of space-time trellis coding is developed for the peculiar UWB signalling structure. Finally, thanks to a novel closed-form ap- proximation, a theoretical comparison is undertaken between any SISO-UWB system and the multiple-antenna UWB systems proposed in this thesis. The results clearly underline the impact of STC on a single-band UWB system in terms of enhanced robustness against timing-jitter effects, higher spectral efficiency and capacity im- provement. These advantages are finally confirmed through the numerical evaluation of the error-rate performance.
