Nambi Seshadri

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We consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas. Data is encoded by a channel code and the encoded data is split into n streams that are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a(More)
This paper describes a channel estimation and tracking scheme for OFDM MIMO systems based on pilot tones. The mean square error of the proposed scheme is derived, and through this we derive optimal training sequences and placement of the pilot tones. It is shown in this paper that minimum mean square (MMSE) channel estimation is obtained with equipowered,(More)
We introduce a new class of space-time codes called super-orthogonal space-time trellis codes. These codes combine set partitioning and a super set of orthogonal space–time block codes in a systematic way to provide full diversity and improved coding gain over earlier space–time trellis code constructions. We also study the optimality of our set(More)
Convolutional ( i ) I ~~~~~~r I Encoder Abstract-A list Viterbi decoding algorithm (LVA) produces a rank ordered list of the L globally best candidates after a trellis search. Here, we present two such algorithms, (i) a parallel LVA that simultaneously produces the L best candidates and (ii) a serial LVA that iteratively produces the kth best candidate(More)