Mobile cellular communications with base station antenna arrays

Abstract: This thesis deals with the problem of increasing thespectrum efflciency of cellular systems by the use of antennaarray base stations. The focus of the thesis is on downlinktransmission in frequency division duplex systems. i.e.,systems with different up and downlink carrier frequency. In ashort summary the thesis:    Proposes five reasonable propagation models.    Uses these models to design and analyze three differentbeamformers: The maximum desired power (MDP), the summedinterference to carrier ratio minimizing (SCIR) and thegeneralized-SCIR beam-former    Introduces three capacity enhancement approaches: samesector frequency reuse (SSFR), reduced cluster size withoutnulling (RCS-WON) and reduced cluster size with nulling(RCS-WIN).    Proposes channel allocation, power control. andbeamforming algorithms for these approaches.    Estimates the "outage probability" {probability ofinsufficient quality), for SICR-SSFR. SICR-RCS-WON andSICR-RCS-WIN. using simulations as well as analyticalanalysis, as a function of critical parameters.    Investigates the capacity enhancement achieved with thebase station antenna array as a function of angular spreadingand the number of antennas for SICR-SSFR. SICR-RCS-WON andSICR-RCS-WIN.    Partially verifies the system simulation assumptionsusing real data.    Combines simulation and experimental results to makelikely that three to tenfold capacity enhancement isrealistic using 3 - 18 antenna elements per 120-degree sector(in comparison with a system employing a single antenna persector). The higher capacity enhancements are obtained usingthe more complex approaches    Makes a detailed proposal of a simple and robust downlinkbeamforming algorithm for realizing RCS-WON in GSM (the MDPbeamformer    Simulates this beamformer under realistic networkconditions, using simulated as well as real dataKeywords:antenna arrays, base station, downlink,spectrum efficiency