On the ergodic sum-rate performance of CDD in multi-user systems

The main focus of space-time coding design and analysis for MIMO systems has been so far focused on single-user systems. For single-user systems, transmit diversity schemes suffer a loss in spectral efficiency if the receiver is equipped with more than one antenna, making them unsuitable for high rate transmission. One such transmit diversity scheme is the cyclic delay diversity code (CDD). The advantage of CDD over other diversity schemes such as orthogonal space-time block codes (OSTBC) is that a code rate of one and delay optimality are achieved independent of the number of transmit antennas. In this work we analyze the ergodic rate of a multi-user multiple access channel (MAC) with each user applying such a cyclic delay diversity (CDD) code. We derive closed form expressions for the ergodic sum-rate of multi-user CDD and compare it with the sum-capacity. We study the ergodic rate region and show that in contrast to what is conventionally known regarding the single-user case, transmit diversity schemes are viable candidates for high rate transmission in multi-user systems. Finally, our theoretical findings are illustrated by numerical simulation results.Comment: to appear in Proceedings of 2007 IEEE Information Theory Workshop (ITW) in Lake Taho

Feed ingredients available in India and their potential nutritional value

Development of practical feed formulations depend upon information on two major aspects; the nutritional requirements of the animals and the nutritive value of the potential feed ingredients. Once information on these aspects along with other essential parameters, become available for a specific species and size, it should be possible to develop low-cost practical feeds using linear programming. During the past two decades there has been a phenomenal increase in research activities relating to identification of raw materials for formulating feed ingredients both in the developed and developing nations of the world

Vitamin requirements of finfish and prawns

Vitamins are complex organic substances, usually of comparatively small molecular size (molecular weight usually less than 1000). They are distributed in feedstuffs in small quantities and form a distinct entity from other major and minor food components (Cho et a_l., 1985). The importance of vitamins as essential constituents in the diets of animals came to light in the early part of this century and during the past five decades active and rapid progress in vitamin research was made almost in all the coMmercially important specie

Enhanced Trustworthy and High-Quality Information Retrieval System for Web Search Engines

The WWW is the most important source of information. But, there is no guarantee for information correctness and lots of conflicting information is retrieved by the search engines and the quality of provided information also varies from low quality to high quality. We provide enhanced trustworthiness in both specific (entity) and broad (content) queries in web searching. The filtering of trustworthiness is based on 5 factors – Provenance, Authority, Age, Popularity, and Related Links. The trustworthiness is calculated based on these 5 factors and it is stored thereby increasing the performance in retrieving trustworthy websites. The calculated trustworthiness is stored only for static websites. Quality is provided based on policies selected by the user. Quality based ranking of retrieved trusted information is provided using WIQA (Web Information Quality Assessment) Framework

Development of artificial feeds for finfishes

successful fish culture depends upon provision of diets coritaining an appropriate balance of essential nutrients and adequate level of energy to permit the most efficient growth of fish. Application of modern techniques, with very high production potentials, demands supply of nutritionally balanced complete feeds in intensive sys-tems and suppLemental feeds in semi-intensive system

Mycotoxins in feeds and their impact on fish and shrimp - Winter school on recent advances in diagnosis and management of diseases in mariculture, 7th to 27th November 2002, Course Manual

Mycotoxins are a group of ubiquitous chemical compounds, widely diverse in their structures and toxic effects, produced by a variety of fungi. The name mycotoxin combines the Greek word for fungus 'mykes' and the Latin word 'toxicum' meaning poison

Aquafeed biotechnology-an overview

Aquafarming is emerging as a successful small-scale bio-industry in India. In order to sustain this industry an organized feed industry is essential to manufacture and supply quality controlled compounded feeds for the different stages and production systems The exogenous feeds used in aquaculture can be broadly grouped into (i) supplementary feeds and (ii) complete feeds. Supplementary feeds, by and large are empirical formulations, which do not provide the essential nutrients in adequate levels and balanced proportions as in the case of complete feeds