Channel Estimation on the bases of Multiuser Space time coding
Vijay Kumar1, Geetu2
1Vijay Kumar, Electronics and Comm. Engineering, Punjab Technical University, Punjab College of Engg. and Technology, AICTE, Distt. Mohali, India,
2Geetu, Electronics and Comm. Engineering, Punjab Technical University, Punjab College of Engg. and Technology, AICTE, Distt. Mohali, India,
Manuscript received on July 01, 2012. | Revised Manuscript received on July 04, 2012. | Manuscript published on July 05, 2012. | PP: 313-315 | Volume-2, Issue-3, July 2012. | Retrieval Number: C0797062312/2012©BEIESP
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© The Authors. Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: In wireless transmission the randomness of the communication channel leads to random fluctuation in the received signal. This fluctuation known as fading. The fading is a fundamental problem in wireless communications because of this fading effect we cannot get exact signal at the receiver side. So to improve the signal performance at the receiver side diversity technique is the best method. Diversity defined as the method of conveying information through multiple independent random fades. Diversity gain results multiple paths between base station and user terminal and coding gain results from how symbols are correlated across transmit antennas. Antenna selection reduces the system cost and complexity by reducing the number of radio frequency (RF) chains while still retaining full diversity. Space time coding arises from a technique known as diversity. This technique uses multiple-input and multiple output (MIMO) concepts to overcome the problem of fading and interference in a wireless channel. Wireless communication using multiple-input multiple-output (MIMO) systems enables increased spectral efficiency for a given total transmit power. Increased capacity is achieved by introducing additional spatial channels that are exploited by using space-time coding. The purpose of paper is to development of fundamental space-time (ST) coding and modulation methods to achieve the gains provided by multiple antennas, in terms of both improved robustness of the link and a higher spectral efficiency. Space time codes (STC) provides the details of the encoding and decoding procedures. The codes are designed on an information theoretic criterion. This paper presents the progress made towards determining the capacity and diversity benefits of multiple antennas under different assumptions about the underlying channel. Simulations suggest that the resulting codes allow for effective high-rate data transmissions in multiple-antenna communication systems. Rayleigh channel model and evaluate its performance in term of BER. Finally, the simulation results will be used to analyze and compare their performance. The research will be conducted in MATLAB environment.
Keywords: Diversity, space-time code, fading channels, wireless communications.