Space–time trellis code

Space–time trellis codes (STTCs) are a type of space-time code used in multiple-antenna wireless communications. This scheme transmits multiple, redundant copies of a trellis (or convolutional) code distributed over time and a number of antennas ('space').

History

STTCs were discovered by Vahid Tarokh et. al in 1998^1,2.

How it works

These multiple, 'diverse' copies of the data are used by the receiver to attempt to reconstruct the actual transmitted data. For a STC to be used, there must necessarily be multiple transmit antennas, but only a single receive antennas is required; nevertheless multiple receive antennas are often used since the performance of the system is improved by so doing.

Comparasons with Space-Time Block Codes

In contrast to space–time block codes (STBCs), they are able to provide both coding gain and diversity gain and have a better bit-error rate performance.

• However, current STBCs are based on trellis codes. This makes these codes more complex than STBCs to encode and decode; they rely on a Viterbi decoder at the receiver where STBCs need only linear processing.

References

1. Vahid Tarokh, Nambi Seshadri, and A. R. Calderbank, "Space–time codes for high data rate wireless communication: Performance analysis and code construction", IEEE Trans. Inform. Theory, vol. 44, pp. 744–765, Mar. 1998.
2. Vahid Tarokh, Ayman Naguib, Nambi Seshadri and A. Robert Calderbank, "Space–time codes for high data rate wireless communication: performance criteria in the presence of channel estimation errors, mobility, and multiple paths", IEEE Trans. Commun., vol. 47, no. 2, pp. 199–206, Feb. 1999.