Cross-layer design of admission control policies in code division multiple access communications systems utilizing beamforming | Posted on:2009-09-07 | Degree:Ph.D | Type:Thesis | University:Queen's University (Canada) | Candidate:Sheng, Wei | Full Text:PDF | GTID:2448390005455405 | Subject:Engineering | Abstract/Summary: | | To meet growing demand for wireless access to multimedia traffic, future generations of wireless networks need to provide heterogenous services with high data rate and guaranteed quality-of-service (QoS). Many enabling technologies to ensure QoS have been investigated, including cross-layer admission control (AC), error control and congestion control.;In the first part, a circuit-switched network is considered and an exact outage probability is developed, which is then employed to derive the optimal call admission control (CAC) policy by formulating a constrained semi-Markov decision process (SMDP). The derived optimal policy can maximize the system throughput with guaranteed QoS requirements in both physical and network layers.;In the second part, a suboptimal low-complexity CAC policy is proposed based on an approximate power control feasibility condition (PCFC) and a reduced-outage-probability algorithm. Comparison between optimal and suboptimal CAC policies shows that the suboptimal CAC policy can significantly reduce the computational complexity at a cost of degraded performance.;In the third part, we extend the above research to packet-switched networks. A novel SMDP is formulated by incorporating ARQ protocols. Packet-level AC policies are then proposed. The proposed policies exploit the error control capability provided by ARQ schemes, while simultaneously guaranteeing QoS requirements in the physical and packet levels.;In this thesis, we study the cross-layer AC problem. While previous research focuses on single-antenna systems, which does not capitalize on the significant benefits provided by multiple antenna systems, in this thesis we investigate cross-layer AC policy for a code-division-multiple-access (CDMA) system with antenna arrays at the base station (BS). Automatic retransmission request (ARQ) schemes are also exploited to further improve the spectral efficiency.;In the fourth part, we propose a connection admission control policy in a connection-oriented packet-switched network, which can guarantee QoS requirements in physical, packet and connection levels. By considering joint optimization across different layers, the proposed optimal policy provides a flexible way to handle multiple QoS requirements, while at the same time, maximizing the overall system throughput. | Keywords/Search Tags: | Admission control, System, Qos requirements, Multiple, Policy, Cross-layer, Policies, CAC | | Related items |
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