Sommersemester 03

Combination of Space-Time Codes with Forward Error Correction (FEC)

Supporting high data rates for broadband (multimedia-) data access will be important for future wireless communication systems. The use of multiple transmit and/or receive antennas (MIMO = multiple input multiple output) makes those high data rates on a rich-scattering wireless channel possible. There are two basic techniques for these systems, namely space-time coding to improve link reliability and spatial multiplexing to increase spectral efficiency. Space-time codes introduce temporal and spatial correlations into signals transmitted from different antennas, in order to combat the fading effects by utilizing diversity of the communication channel. The idea of spatial multiplexing is to "break up" the data stream into several parallel data streams, which are then transmitted simultaneously from the transmit antennas.

Recently the Wireless Communication Group of the Communication Technology Laboratory developed a very flexible and efficient class of codes [1], which allows a combination of space-time coding and spatial multiplexing. We refer to them as Linear Scalable Dispersion (LSD) Space Time Codes.

In this project the concatenation of the LSD Codes with forward error correction (FEC) codes, like trellis codes or block based turbo codes, should be investigated. The aim is first to identify a good engineering tradeoff in terms of effective throughput, bit error performance and computational (decoder-) complexity for this concatenation. A further goal is to determine the gain, which can be achieved by soft-decision decoders instead of hard-decision decoders.

[1] A. Wittneben, M. Kuhn, "A new concatenated linear high rate space-time block code", Proc. VTC, May 2002.
[2] T.H. Liew, L. Hanzo, "Space-time codes and concatenated channel codes for wireless communications", Proc. of the IEEE, 2002.

Subject area Wireless communications, MIMO, space-time codes, channel coding, decoding
Type of work 40% Theory, 40% Simulation, 20% Software
Student Tobias Koch, Till Quack
Supervisor Dr. Ingmar Hammerström
Professor Prof. Dr. Armin Wittneben