Parallel decoding of turbo codes using multi-point trellis termination and collision-free interleavers

The UMTS turbo encoder is composed of parallel concatenation of two Recursive Systematic Convolutional (RSC) encoders which start and end at a known state. This trellis termination directly affects the performance of turbo codes. This paper presents performance analysis of multi-point trellis termination of turbo codes which is to terminate RSC encoders at more than one point of the current frame while keeping the interleaver length the same. For long interleaver lengths, this approach provides dividing a data frame into sub-frames which can be treated as independent blocks. A novel decoding architecture using multi-point trellis termination and collision-free interleavers is presented. Collision-free interleavers are used to solve memory collision problems encountered by parallel decoding of turbo codes. The proposed parallel decoding architecture reduces the decoding delay caused by the iterative nature and forward-backward metric computations of turbo decoding algorithms. Our simulations verified that this turbo encoding and decoding scheme shows Bit Error Rate (BER) performance very close to that of the UMTS turbo coding while providing almost %50 time saving for the 2-point termination and %80 time saving for the 5-point termination.

Increasing the speed of parallel decoding of turbo codes

Turbo codes experience a significant decoding delay because of the iterative nature of the decoding algorithms, the high number of metric computations and the complexity added by the (de)interleaver. The extrinsic information is exchanged sequentially between two Soft-Input Soft-Output (SISO) decoders. Instead of this sequential process, a received frame can be divided into smaller windows to be processed in parallel. In this paper, a novel parallel processing methodology is proposed based on the previous parallel decoding techniques. A novel Contention-Free (CF) interleaver is proposed as part of the decoding architecture which allows using extrinsic Log-Likelihood Ratios (LLRs) immediately as a-priori LLRs to start the second half of the iterative turbo decoding. The simulation case studies performed in this paper show that our parallel decoding method can provide %80 time saving compared to the standard decoding and %30 time saving compared to the previous parallel decoding methods at the expense of 0.3 dB Bit Error Rate (BER) performance degradation.

Understanding the Effect of Television Advertising on Women's Attitudes and Purchase Intentions Towards Beer: A Study of Three Major Brands.

Abstract Purpose of Paper: The market for beer in the UK is now mature and sales have been stable at around £16bn for about ten years (Mintel 2014). More recently, there have been changes in the market as consumers have switched from bigger mainstream brands to a growing number of smaller craft beers. However, in order to grow further significantly, the industry needs to explore new market segments and find new consumers for beer. So far, it is estimated that only 1.3m women in the UK drink beer (O'Reilly, 2014; Mail Online, 2015). Women are therefore an underexplored segment and present the main growth opportunity for beer drinking in the UK. However, most beer television advertising has traditionally been aimed at the male audience and there have been suggestions that some of this advertising has been seen as unpopular with or even insulting to women (Jackson, 2013; Zwarun et al., 2006). The Chief Executive of major brewer SAB Miller, which owns the Foster's brand, has recently written that, 'We have to acknowledge that core lager advertising, for many years, was either dismissive of, or insulting to, women.' (Shubber, 2015). If women are to be the new consumers and the future target for beer advertising, there is therefore a significant gap in the knowledge and literature concerned with how women differ from men in responding to the television advertising produced by beer brands and it is important that this gap in knowledge is addressed. The purpose of this paper is therefore to explore the effect of the television advertising of the three top selling UK beer brands on women's attitudes and purchase intentions towards those brands. More specifically, the objectives are: 1) To gain an understanding of how female consumers respond to existing beer television advertising, specifically in terms of the ‘likeability’ of the content of TV commercials produced by the three leading UK beer brands among female consumers. 2) To examine the effect of the rational and emotional content, including the use of humour, in television commercials produced by the three leading UK beer brands on the attitudes of female consumers towards those brands. 3) To explore in-depth female consumer attitudes towards the content (message cues and symbolism) of the television commercials produced by the three leading beer brands in the UK and their effect on subsequent purchase intentions for each brand.