Towards Fully Optimized BICM Transceivers

Bit-interleaved coded modulation (BICM) transceivers often use equally spaced constellations and a random interleaver. In this paper, we propose a new BICM design, which considers hierarchical (nonequally spaced) constellations, a bit-level multiplexer, and multiple interleavers. It is shown that this new scheme increases the degrees of freedom that can be exploited in order to improve its performance. Analytical bounds on the bit error rate (BER) of the system in terms of the constellation parameters and the multiplexing rules are developed for the additive white Gaussian Noise (AWGN) and Nakagami-$m$ fading channels. These bounds are then used to design the BICM transceiver. Numerical results show that, compared to conventional BICM designs, and for a target BER of $10^{-6}$, gains up to 3 dB in the AWGN channel are obtained. For fading channels, the gains depend on the fading parameter, and reach 2 dB for a target BER of $10^{-7}$ and $m=5$.Comment: Submitted to the IEEE Transactions on Communication

Motivations behind Attending Fitness Clubs in Bangladesh: A Survey Study on Clubs' Members in Sylhet

Fitness club is a place where people join to have physical exercise. Though it has been practicing from the ancient nomadic lifestyles, the fitness industry is experiencing the boom when Dr. Ken H. Cooper in 1968 released his concepts to prevent the growth of chronic diseases, regular exercise and fitness is essential. This study is descriptive in nature and aims to know the reasons for which the fitness club members attend fitness clubs in Sylhet. 200 members were asked several questions, 99 of whom seems physical exercise improves their health conditions, 81 thinks it develop their self-control, 49 found it as an way to gain status, 79 beliefs it helps to stay away from diabetes. The study will helpful to different individuals interested to practice physical exercise, operators and trainers of fitness clubs and also future researchers. Key words: Fitness club, Motivation, Physical Exercise, Physical Accord

Job Dissatisfaction and Turnover: Bangladesh Perspective

The process of job turnover can be described as job dissatisfaction is the first step, followed by intention to leave, which finally, can result in actual turnover (Mobley et al. 1978; Bannister & Griffith 1986). This article aimed at identifying the empirical evidences of turnover in three different situations: i) being dissatisfied with the previous job, ii) availability of job in the market and iii) (search for) better alternative job as well as identifying the factors affect job dissatisfaction.  In order to collect data for this study a comprehensive questionnaire was distributed to 150 employees of different private and public organization in Bangladesh who already leaved their previous job, of them 140 usable responses were received (drop-out rate: 6.67 percent). The results showed that the rates of turnover in three different situations are 33%, 25% and 52.5% respectively. The most important factors which affect job dissatisfaction are working environment & administration, supervisors & working hours and security of income (future) etc.  A final conclusion of this study is that, the organizations experience excessive rate of job turnover should consider the said factors to retain their employees. Keywords: Job turnover, Turnover situations, Commitment, Job dissatisfaction