Alrabadi, Osama

English

Multi-input-multi-output (MIMO) communication has emerged as a promis-ing technology for meeting the increasing demand on higher data rates. Thetechnology exploits the spatial resource dimension by sending the datas-treams to different locations in the multi element array (MEA) domain whiledecoding the signals at the receive end based on the signalsŠ unique spatialsignatures. To this end, the MEA is conventionally assumed to be attachedto a number of radios for independently modulating and up-converting (de-modulating and down-converting) the set of signals at the transmit (receive)end.While the implementation of a MIMO system is affordable at basestations(BS) and access points (AP), this is not true when considering simple, low-cost, battery-based mobile terminals with limited physical area. It is thesubject of this thesis to bring a new philosophy regarding the design ofreduced complexity MIMO systems by revisiting the MIMO wireless prop-agation from a signal space point of view. The main objective is to enableMIMO transmit functionalities with a sole radio and a single RF chain.The general approach for achieving the aforementioned objective is to mod-ulate one datastream conventionally to a single antenna element while mod-ulating the other datastreams in the analogue RF domain, using simpleswitched antenna systems (SAS) or sophisticated reactance-assisted antennasystems.The use of a SAS is found simple to implement, but can hardly handle highorder signal formats, and is best suited for binary phase shift keying (BPSK)signal formats. The idea there is to encode the remaining datastreams tothe active antenna index by moving the excitation point using an RF switch.In the second case, reactance-assisted antenna systems are found importantfor scaling the single-radio MIMO objective to high order signaling dimen-sions. The idea is to exploit a number of passive radiators surrounding thecentral driving one for creating the desired multiplexing relations of a setof predefined basis beams. By this, information is encoded over the an-gular variations of the beampattern, which finally conveys the datastreamsover the propagation channel to the intended receiver. However the secondtechnique requires a complex baseband control circuitry when compared tothe SAS approach. The proposed approach is finally validated in an indooroffice environment using a 2.6 GHz prototype. The experiments show thatthe proposed beamspace MIMO approach provides performance compara-ble to a conventional MIMO system, but at a reduced size and hardwarecomplexity

MIMO Communication Using Single Feed Antenna Arrays

https://vbn.aau.dk/ws/files/316422953/Osama_Thesis.pdf

MIMO Communication Using Single Feed Antenna Arrays

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