Intelligent wireless networking
Intelligent wireless networking
In this thesis we have enhanced the achievable performance of the Code Division Multiple Access (CDMA) based Universal Mobile Telecommunication System's (UMTS) Terrestrial Radio Access (UTRA) using both adaptive beamformers and adaptive modulation. A Multi-Carrier CDMA (MC-CDMA) system is also investigated. A specific family of spreading codes, which are known as Loosely Synchronized (LS) codes exhibits a so-called Interference Free Window (IFW), where both the autocorrelation and cross-correlation values of the codes become zero. Hence, LS codes have the potential of increasing the capacity of CDMA networks. The beneficial effect of LS spreading codes on the UTRA-like Frequency Division Duplex (FDD) and Time Division Duplex (TDD) CDMA cellular mobile's network performance was also investigated. More specifically, both single-element antennas, as well as two- and four-element adaptive antenna arrays (AAAs) located at the base stations were used. This work was then extended by investigating the achievable network capacity, when combining Adaptive Quadrature Amplitude Modulation (AQAM) techniques and AAAs. The effect of the cell size as well as that of the Signal-to-Interference plus Noise Ratio (SINR) threshold on the UTRA-like FDD CDMA cellular mobile network's performance was also investigated.
The UTRA TDD CDMA cellular mobile network is potentially more flexible than the FDD mode and hence it has the ability of supporting the asymmetric use of a duplex channel. However, the TDD technique is more vulnerable to cochannel interference than the FDD mode. Hence the attainable performance of the UTRA-like FDD and TDD/CDMA networks was compared in terms of their network capacity, grade of service (GOS) and their mean transmission powers in the context of log-normal shadow faded propagation environments. The key parameters of the UTRA TDD/CDMA Handover (HO) and Power Control (PC) based on the 3rd Generation Partnership Project (3GPP) were studied. A relative pilot power based hard handover technique and a frame-delay based power adjustment model used in power control were developed. A novel Genetic Algorithm (GA) assisted timeslot scheduling scheme was also proposed, in order to search for the optimal timeslot allocation, which avoided the severe inter-cell interference imposed by using the same carrier for both uplink and downlink transmission in a UTRA TDD/CDMA system. Finally, the performance benefits of GA-assisted timeslot scheduling were quantified.
University of Southampton
Ni, Song
84c6cbce-a7fa-4849-b3f8-c0ddf7b8cc93
2005
Ni, Song
84c6cbce-a7fa-4849-b3f8-c0ddf7b8cc93
Ni, Song
(2005)
Intelligent wireless networking.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
In this thesis we have enhanced the achievable performance of the Code Division Multiple Access (CDMA) based Universal Mobile Telecommunication System's (UMTS) Terrestrial Radio Access (UTRA) using both adaptive beamformers and adaptive modulation. A Multi-Carrier CDMA (MC-CDMA) system is also investigated. A specific family of spreading codes, which are known as Loosely Synchronized (LS) codes exhibits a so-called Interference Free Window (IFW), where both the autocorrelation and cross-correlation values of the codes become zero. Hence, LS codes have the potential of increasing the capacity of CDMA networks. The beneficial effect of LS spreading codes on the UTRA-like Frequency Division Duplex (FDD) and Time Division Duplex (TDD) CDMA cellular mobile's network performance was also investigated. More specifically, both single-element antennas, as well as two- and four-element adaptive antenna arrays (AAAs) located at the base stations were used. This work was then extended by investigating the achievable network capacity, when combining Adaptive Quadrature Amplitude Modulation (AQAM) techniques and AAAs. The effect of the cell size as well as that of the Signal-to-Interference plus Noise Ratio (SINR) threshold on the UTRA-like FDD CDMA cellular mobile network's performance was also investigated.
The UTRA TDD CDMA cellular mobile network is potentially more flexible than the FDD mode and hence it has the ability of supporting the asymmetric use of a duplex channel. However, the TDD technique is more vulnerable to cochannel interference than the FDD mode. Hence the attainable performance of the UTRA-like FDD and TDD/CDMA networks was compared in terms of their network capacity, grade of service (GOS) and their mean transmission powers in the context of log-normal shadow faded propagation environments. The key parameters of the UTRA TDD/CDMA Handover (HO) and Power Control (PC) based on the 3rd Generation Partnership Project (3GPP) were studied. A relative pilot power based hard handover technique and a frame-delay based power adjustment model used in power control were developed. A novel Genetic Algorithm (GA) assisted timeslot scheduling scheme was also proposed, in order to search for the optimal timeslot allocation, which avoided the severe inter-cell interference imposed by using the same carrier for both uplink and downlink transmission in a UTRA TDD/CDMA system. Finally, the performance benefits of GA-assisted timeslot scheduling were quantified.
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Published date: 2005
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Local EPrints ID: 465686
URI: http://eprints.soton.ac.uk/id/eprint/465686
PURE UUID: b0b017b1-ca6d-4081-93a6-c7f8a23a244b
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Date deposited: 05 Jul 2022 02:34
Last modified: 16 Mar 2024 20:19
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Author:
Song Ni
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