Cooperative mimo communications - information theoretical limits and practical coding strategies
- Autores: Sebastien Simoens
- Directores de la Tesis: José Vidal Manzano (dir. tes.), Olga Muñoz Medina (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2009
- Idioma: español
- Tribunal Calificador de la Tesis: Javier Rodríguez Fonollosa (presid.), Antonio Pascual Iserte (secret.), M. Dohler (voc.), Are Hjørungnes (voc.)
- Materias:
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- Resumen
Early works on the capacity of the wireless relay channel date back more than 30 years. In its genuine version this channel consists of three nodes: a source transmits data to a destination with the help of a relay. In the Information Theory community, various coding strategies have been proposed and their achievable rates have been derived for the three-node relay channel and its extensions to multiple relays, multiple sources and destinations. In the Signal Processing and Wireless Communications community, various questions related to the implementation and performance of relaying have been addressed, such the diversity and multiplexing characteristics of the relay channel, distributed space-time coding, linear processing at the source, relay and destination, etc.
Recently the topic of cooperative relaying has received a lot of attention in the academia and in the industry. Cooperative relaying refers to the fact that advanced coding strategies for the relay channel involve the distribution of coding and decoding functions at several nodes which cooperate in order to maximize the achievable rate between the source(s) and the destination(s). The recent interest in cooperative relaying and cooperative communications in general is motivated by the explosion of wireless internet traffic and can be summarized by the following question: can cooperative relaying substancially increase the spectral efficiency of future Broadband Wireless Access (BWA) networks? In this thesis we do not pretend to provide a final answer to this question, but at least we try to contribute on several aspects. The first one is the derivation of capacity bounds for the Multiple Input Multiple Output (MIMO) relay channel with full Channel State Information (CSI), i.e. in the case when all devices are equipped with multiple-antennas and have the capability to exploit channel knowledge at the transmitter side. We propose source and relay precoder optimization procedures which allow the efficient computation of the Cut Set Bound and of achievable rates for the Decode-and-Forward (DF), Compress-and-Forward (CF), and for the more recent distributed CF coding schemes. In a second part of the thesis, we try to exploit these new information-theoretic bounds in order to predict the throughput performance of future BWA networks. We review several implementation-related constraints at the device and link levels (duplexing, broadband transmission, practical modulation and coding, power constraints, imperfect CSI etc), and also at the system-level (deployment topology, macroscopic propagation effects, interference). We analyze their effect analytically and/or by simulations and investigate how capacity bounds can be modified to model them.
