Quality of Service Support for MPLS-based
Scott Fowler, Sherali Zeadally, and Abdelhamid Mellouk
Invited Book chapter, in the “Quality of Service Mechanisms in Next Generation
Heterogeneous Networks: Utopia or Reality”, edited by Wiley/ISTE
Publishing, to be published in April-June 2008.
On Construction of the (24, 12, 8) Golay Code
X.-H. Peng and P.G. Farrell
IEEE Trans. on Information Theory, Vol. 52, No. 8, Aug.
2006, pp. 3669- 3675.
product array codes are used to construct the (24, 12, 8) binary
Golay code through the direct sum operation. This construction
provides a systematic way to find proper (8, 4, 4) linear block
component codes for generating the Golay code, and it generates and
extends previously existing methods that use a similar construction
framework. The code constructed is simple to decode.
Fast and accurate tactile sense feedback for
an innovative flexible digit for clinical applications.
I. Petra, D.J. Holding, X. Ma, P.N. Brett and K.J. Blow
Electronic Letters, Vol 42, No 14, July 2006,
pp 790 - 792. ISSN: 0013-5194 , doi: 10.1049/el:20064388
An embedded signal processing system that uses a low numbers of
sensors and cascaded neural networks to provide tactile feedback for a
novel flexible digit for clinical applications is described. The
design has been implemented as an FPGA-based application-specific
digital signal processing circuit that computes real-time tactile
feedback with clinically significant accuracy.
Based on Distributed Coding Schemes in Wireless Networks
X.-H. Peng and X. Gu
BT Technology Journal, Vol. 24, No. 2, April 2006, pp.97-102.
This paper examines
both research and development challenges in the area of co-operative
diversity for enhancing channel capacity in wireless communications
networks. In particular, the role played by the distributed coding
protocols in achieving diversity gains is investigated in connection
with the co-operative communications model built via relay channels.
A coding scheme suitable for the nodes working collaboratively in
this environment is also presented.
MIMO Systems for Broadband Wireless Communications
X. Gu, X.-H. Peng and G.-C. Zhang
BT Tech. Journal, Vol. 24, No. 2, April 2006, pp.90-96.
The emergence of
broadband wireless access (BWA) and mobility poses significant
challenges to the future telecommunications landscape. Multiple input
multiple output (MIMO) is a potential technology that can be used to
improve system performances such as coverage, capacity and data rates
for broadband wireless networks. Although this technology has proved
to be beneficial for both current and future services by many
research results, it is not clear how these benefits can be
practically achieved with a MIMO system. Fundamental issues on
capacity enhancement and performance limits need to be addressed
before operators will be willing to deploy MIMO systems in their
networks. This paper addresses some of the key issues that remain
open regarding MIMO technology for BWA. The paper focuses on MIMO
channel modelling and capacity analysis.
Radio Range Adjustment for Energy Efficient Wireless Sensor Networks.
Q. Gao, K.J. Blow, D. J. Holding, I. W. Marshall, X. H. Peng, J.
Ad-Hoc Networks Vol. 4, No. 1, Jan 2006, pp 75 - 82. ISSN: 1570-8705.
In wireless ad hoc
sensor networks, energy use is in many cases the most
important constraint since it corresponds directly to
operational lifetime. Topology management schemes such as GAF
put the redundant nodes for routing to sleep in order to save
the energy. The radio range will affect the number of
neighbouring nodes, which collaborate to forward data to a
base station or sink. In this paper we study a simple linear
network and deduce the relationship between optimal radio
range and traffic. We find that half of the power can be saved
if the radio range is adjusted appropriately compared with the
best case where equal radio ranges are used.
Making Motes Intelligent: An Agent-Based Approach to Wireless Sensor Networks
Dimitrios Georgoulas and Keith Blow,
WSEAS Transactions on Communications 5 515-522 (2006)
Erasure-Control Coding for Distributed Networks
IEE Proceedings on Communications, Vol. 152, No. 6, Dec. 2005, pp.1075-1080.
coding has seen itself quickly emerge as a very promising technique
in relatively new territory: distributed networks, where computing,
communication and storage are extensively involved. In this
environment, the distribution of rich media files to a large user
population and the distribution of mission-critical data present
special challenges for service providers and enterprises. Ensuring
quality of service to these applications requires a combination of
reliability, speed and scalability. Traditional packet-based networks
endure poor end-to-end performance when packet loss rates are high
and a simple error-control strategy (through re-transmission) is
applied. The paper will show how erasure-control coding, a special
channel coding technique, plays an important part in promoting fault
tolerance, and consequently quality of service across the network.
Additionally, the construction of a class of
maximum-distance-separable (MDS) array erasure codes is presented,
which can be used in an adaptive way to efficiently control packet
losses in a fluctuating network environment.
Analysis of Energy Conservation in Sensor
Q.Gao, K.J.Blow, D.J.Holding and I. Marshall,
J Wireless Networks (WINET), Vol 11,
No. 6, pp 787 - 794, ACM/ Kluwer, Nov 2005. ISSN:1022-0038. [PDF]
In this paper we use the Erlang theory to
quantitatively analyse the trade offs between energy conservation and
quality of service in an ad-hoc wireless sensor network. Nodes can be
either sleeping, where no transmission or reception can occur, or
awake where traffic is processed. Increasing the proportion of time
spent in the sleeping state will decrease throughput and increase
packet loss and delivery delay. However there is a complex
relationship between sleeping time and energy consumption. Increasing
the sleeping time does not always lead to an increase in the energy
saved. We identify the energy consumption profile for various levels
of sensor network activity and derive an optimum energy saving curve
that provides a basis for the design of extended-life ad hoc wireless
Simple Algorithm for Improving Time
Synchronization in Wireless Sensor Networks
Q.Gao, K.J.Blow, D.J.Holding,
Electronics Letters, 40, July 2004, pp 889-891 [PDF]
We present a simple method for improving time
synchronisation suitable for use in ad-hoc sensor networks where
processing power is limited. The technique is local and uses Bayesian
estimation. A simple simulation shows an improvement of about four
Optimal Augmentation of Product Codes
X.-H. Peng and P.G. Farrell
Electronics Letters, vol. 40, June 2004, pp. 750-752.
A systematic technique for constructing augmented product codes is
presented. These augmented codes have optimum or near-optimum rates,
and can be decoded just as efficiently as the original product code.
Determining Design Parameters for Ad Hoc Wireless Sensor Networks
Q.Gao, K.J.Blow, D.J.Holding and I. Marshall,
Proceedings of IEEE ETFA'2003, Lisbon, Portugal (2003)
Adaptive Soft-decision Decoding in Two Dimensions
X.-H. Peng, P.G. Farrell, and P. Coulton
Information, Coding & Mathematics, published by Kluwer Academic
Publishers, May 2002, pp.299-321, ISBN: 1-4020-7079-9.
To achieve efficient
soft-decision decoding for two-dimensional product and array codes,
an adaptive decoding scheme is proposed. In the scheme, the special
structure of these codes has been fully exploited, resulting in a
method for effective use of combined hard- and soft-decision decoding
of component codes, As a result, a substantial reduction in decoding
complexity is obtained, especially when channel conditions are good.
We will show that the decoding algorithm presented can guarantee
bounded soft distance performance, while simulation results indicate
even better decoding performance and an improvement over similar
previous decoding methods. Turbo decoding is about 1dB better in
performance, but at the cost of a very significant increase in
DES Developed In Handel-C
M Mylonas, D.J Holding, K.J.Blow,
Energy Efficiency Design Challenge in Sensor Networks
Proceedings LCS, 209-211, (2002)
Q.Gao, D.J.Holding, Y. Peng and K.J.Blow,
Proceedings LCS, 69-72, (2002)
Optimal Soft-Decision Decoding for Multilevel Block Modulation Codes
X.-H. Peng and A. Burr
IEE Proceedings on Communications, Vol. 148, No. 6, Dec. 2001, pp.333-338.
multistage trellis decoding method is examined when applied to
multilevel block modulation codes. It is shown how low decoding
complexity can be achieved using this method, while performing
maximum-likelihood decoding. As the decoding complexity involved is
shown to be channel-quality dependent, the actual decoding
computational burden becomes very low when the system signal-to-noise
ratio is high. A way of constructing the generator matrix for
multilevel block modulation codes is demonstrated, in order to build
a proper trellis for decoding.
Adaptive Soft-Decision Decoding for Array Codes
X.-H. Peng, and P.G. Farrell
European Trans. on Telecommunications, Vol. 12, No. 6, Nov.-Dec. 2001, pp.487-499.
adaptive decoding scheme is introduced that achieves efficient
soft-decision decoding for row-and-column parity array codes. The
special structure of array codes is exploited to make effective use
of hard-decision methods to realize soft-decision decoding. This
leads to considerable reduction in decoding complexity as the amount
of soft-decision computation varies with channel conditions. It is
shown that the new decoding algorithm guarantees bounded distance
performance. Simulation results indicate that the actual improvement
of decoding performance over uncoded systems and previous decoding
methods is significant.
A possible secure solution for mobile agents
Peng, Y., Holding, D.J. and Blow, K.J.,
Proc. 2001 Int. Conf. on Intelligent Agents Web Technologies and Internet Commerce, IAWTIC'2001, Las Vegas, (2001)