Showing papers by "Amitava Ghosh published in 2009"

Method and system for codebook-based closed-loop mimo using common pilots and analog feedback

Abstract: A method and system that enables the usage of sounding-based feedback or analog feedback in a MIMO communication system with non-beamformed or broadcast pilot symbols is disclosed. The mobile station may employ a feedback channel to send a sounding waveform to a base station, a feedforward channel to receive from the base station codebook weights derived from the send sounding waveform, a receiver to receive communication from the base station, and a processor to detect beamformed data from the received communication and received codebook weights from the base station. The base station processes the sounding waveform to determine codebook weights on groups of subcarriers. Additionally, the base station transmits the beamformed payload and broadcast pilots to the mobile station.

Multi-Antenna Systems for LTE eNodeB

Abstract: Long-term evolution (LTE) of the UMTS network provides improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. To achieve these enhancements, a new design for the air interface including state-of-art multi-antenna technology was developed. This article describes multi-antenna schemes for UMTS LTE and provides system performance of different multi-antenna schemes under various scenarios.

Performance of Frequency Selective Scheduling and Fractional Frequency Reuse Schemes for WIMAX

Abstract: WiMaX is the commercial name for the 4G OFDM based wireless broadband data transmission standard 802.16, developed by IEEE ([1] and [2]). It is currently being deployed in several countries around the world. Sub-channels (which are the basic unit of resource allocation) are formed by grouping together sub-carriers in one of two formats - PUSC or AMC. In PUSC the set of sub-carriers in a sub-channel are distributed throughout the bandwidth while in AMC the sub-carriers in a subchannel are contiguous within a portion of the bandwidth. In this paper we study two candidates that offer the potential to improve the system performance of PUSC and identify scenarios when this improvement is possible: (i) compare the performance of PUSC with two flavors of AMC; and (ii) study how the PUSC performance can be improved by a Fractional Frequency Reuse (FFR) scheme that tries to perform interference mitigation/co-ordination and improve the throughput of users at the edge of the cell.