Details of Grant 

EPSRC Reference:	GR/H88077/01
Title:	DATA TRANSMISSION TECHNIQUES FOR CHANNELS WITH HIGH LEVELS OF NON-GAUSSIAN NOISE
Principal Investigator:	Honary, Professor B
Other Investigators:
Researcher Co-Investigators:
Project Partners:
Department:	Engineering
Organisation:	Lancaster University
Scheme:	Standard Research (Pre-FEC)
Starts:	01 September 1992	Ends:	31 August 1995	Value (£):	9,880
EPSRC Research Topic Classifications:	Digital Signal Processing
EPSRC Industrial Sector Classifications:
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Panel History:
Summary on Grant Application Form
According to the working programme, the research Lancaster Communications Research Centre was carried out in three major directions:(i) Spectral Shaping Codes (Lancaster);(ii) Embedded Modulation and Embedded ECC (Hull & Lancaster);(iii) Overall Transmission Protocol ( Hull & Lancaster).This progress report briefly describes the results achieved in each of these areas carried out at the Communications Research Centre at Lancaster University.Progress:Current Status:Spectral Shaping Codes:Spectral shaping codes represent a new class of codes that allow to minimise the effect of co-channel narrowband interference by placing a spectral nulls at points in the channel bandwidth where high levels of interfering signals are present. This research is concerned with the design and investigation of block codes which are designed to have a specified power spectrum. A new spectral shaping techniques, called Multiple Modification Vector Technique , has been developed. The technique is based on the use of Generalised Array Codes (GACs), allowing alteration of the spectrum of an encoded signal in real time to match channel characteristics. In addition, the designed codes can be efficiently decoded using their minimal trellises, while the minimum Hamming distance of the codes is remained unchanged. The selection of modification vectors is the critical aspect of this scheme. A design method allowing the selection of particular spectral characteristics is being investigated, the emphasis on creating spectral nulls at specific frequencies. Embedded Modulation and Embedded ECCIn many practical applications, such as time varying channels, is desired to obtain reliable data communication while maintaining a high rate of information and low implementation complexity. As an outcome of this research project, a new class of embedded combined coding and modulation scheme has been developed. The basic principle is that as channel conditions degrade, more powerful scheme is used and vice versa. The technique has been implemented for both block and convolution codes and efficient embedded trellis coded modulation schemes have been designed and simulated. Overall Transmission System ProtocolThe ARQ principle has been recognised as one of the most effective and robust protocols for transmission over HF time-varying channels. However, as the channel conditions deteriorate the number of repetitions becomes excessive, providing long delays in data transmission. A new hybrid ARQ protocol with the memory has been proposed and investigated during the research period. The protocol can be viewed as a combination of template correlation, embedded channel coding and modulation, multiplexing and error detection and can be applied to full duplex transmission. Simulation results have shown that the designed ARQ is capable of working effectively over a wide range of channel conditions, providing higher throughput and reliable communication.
Key Findings
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Organisation Website:	http://www.lancs.ac.uk