| Summary: | Small mobile devices which have an ability to access the world wide web (WWW) wirelessly are
in demand of late. This demand is attributed to the fact that video and audio streaming are cost
effectively accessible via the WWW through wireless fidelity (Wi-Fi). This high demand for
cheap real-time multimedia access via Wi-Fi makes it imperative for researchers to develop a
wireless local area network (WLAN) standard, such as IEEE (802.11n), that has high data
throughput and/or link reliability. The current drawback with the IEEE (802.11n) standard is that
it is not power efficient for battery powered small mobile devices because of the high complexity
multiple-input-multiple-output (MIMO) scheme implemented within the standard. Spatial
modulation (SM) is a recently proposed low complexity MIMO scheme that can achieve high
data throughput with good link reliability whilst being power efficient for small mobile devices.
This study is aimed at further improving data throughputs of SM and also determining the bit
error rate (BER) performance of SM in a city centre environment.
Conventional spatial modulation has been investigated in literature with most research efforts
geared towards improving the BER performance and minimizing receiver complexity of the scheme over non-cascaded fading channels. We propose adaptive M-ary quadrature amplitude
spatial modulation (A-QASM) as a scheme that will improve the average throughput in
comparison to conventional spatial modulation given a target BER constraint. The analytical
BER lower bound is derived for this proposed scheme and validated by the Monte Carlo
simulation results. The simulation results also prove that the average throughput of the proposed
scheme (A-QASM) outperforms that of conventional spatial modulation. The definition for the
received SNR of the A-QASM scheme is also proposed.
In research literature, conventional spatial modulation has been discussed in depth in non-cascaded
wireless fading channels. The performance analysis derived in literature in non-cascaded
wireless fading channels; does not apply in predicting the BER performance of a
mobile device, using conventional spatial modulation, in an environment where there is signal
diffraction (i.e city centre or a forest) which makes the signal susceptible to independent
cascaded fading. This study contributes by developing an analytical framework for the BER lower bound of conventional spatial modulation over cascaded fading channels. Simulation
results closely agree with the derived theoretical framework. === Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.
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