Macrodiversity power control in hierarchical CDMA cellular systems

Kim, J.Y.; Stuber, G.L.; Akyildiz, Ian F.

doi:10.1109/49.914504

Cited by 21 publications

(8 citation statements)

References 18 publications

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“…In [16] the authors suggested tier selection algorithms to improve the uplink capacity of a microcell/macrocell overlaying system. In [12], a macrodiversity scheme was proposed to enable a hierarchical CDMA system to share the same spectrum between the macrocell and the microcell by adopting the SSDT technique in the downlink and the maximal ratio combining technique in the uplink. To our knowledge, in an environment with a cluster of microcells surrounded by macrocells, the downlink capacity of such a CDMA system considering both handoff and power control has not been fully addressed in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of Downlink Power Allocation Mechanisms in Soft Handoff for the WCDMA System with Heterogeneous Cell Structures

2005

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Handoff in heterogeneous cellular networks is one of the hot topics for wireless networks beyond the third generation. We observe that a power exhausting issue may occur in a code division multiple access (CDMA) system with mixed-sized cells. During soft handoff in the downlink transmission, a number of base stations transmit signals to a user simultaneously. Usually, a microcell has a more stringent limitation on the total available power than a macrocell. Thus, ignoring the impact of various cell sizes, the traditional downlink power allocation techniques for soft handoff may easily consume excessive power to serve soft handoff users, while leaving insufficient power for serving other regular users.To resolve such an power exhausting issue in CDMA systems, we investigate different downlink power allocation techniques used in soft handoff subject to the impact of mixed-sized cells. For the single-site power allocation technique we consider the site selection diversity transmission (SSDT) technique, while for the multi-site power allocation we study the link proportional power allocation (LPPA), the quality balancing power allocation (QBPA), and the equal power allocation (EPA) techniques. We find that the multi-site LPPA technique can more efficiently allocate power to both handoff and non-handoff users than others. In an example with the ratio of the micrcocell radius/macrocell radius equal to 1/3, it is demonstrated that LPPA can improve the capacity over EPA, QBPA, and SSDT by 125, 30, and 5%, respectively. By taking account of measurement errors in the same case, the capacity improvements of LPPA over EPA, QBPA, and SSDT become 180, 41, and 23%, respectively.

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Section: Introductionmentioning

confidence: 99%

“…With respect to the performance of heterogeneous CDMA cellular systems, some works have been reported in the literature [10,12,16,22]. In [22], it was concluded that the capacity of a hierarchical cellular system can be improved by integrating downlink power control of microcells and uplink power control of a macrocell.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Downlink Power Allocation Mechanisms in Soft Handoff for the WCDMA System with Heterogeneous Cell Structures

2005

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“…However, the system has to deal with the high inter-layer interference, which is quite serious in such interference-limited networks [2]. Several studies have considered this problem, and proposed solutions such as using different power control algorithms [3] or multi-user detectors [4].…”

Section: Introductionmentioning

confidence: 99%

Non-real time packet transmission for a microcell (hotspot) embedded in CDMA macrocell systems

Ghorashi

Wang

Said

et al.

IEEE International Conference on Communications, 2003. ICC '03.

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In a macrocell network, there will remain some geographical areas within the cell coverage where mobile stations require further services. These are mainly in terms of downloading data, in particular in temporary or permanent hotspot areas, such as exhibitions, conference centers, etc. The objective of this study is to obtain extra capacity for W-CDMA systems by adding hotspot base stations to an already present continuous macrocell layer. IP-based services are offered to local mobile stations, using packet switched transmission without additional bandwidth; i.e. using the same frequency band in both the hotspot and macrocell. In order to maximize the hotspot base station throughput, and at the same time, to minimize the interlayer interference from hotspot to macrocell, a new Link Quality Control scheme is designed. Downlink system level simulations are also carried out to prove the feasibility of the idea and to show the effect of required E b /(I o +N o ) for macrocell users, on the hotspot data throughput.Keywords-Code division multiple access (CDMA); hierarchical cell structures (HCS); link quality control (LQC); packet transmission.

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“…Given the location of an MS and in Cell 1, the probability that the MS is connected to BS is (5) where erfc . Therefore, the probability of an MS in Cell 1 being connected to BS is (6) where is the macrocell radius. Similarly, we can calculate ,…”

Section: A Interference Analysismentioning

confidence: 99%

“…Several studies have been performed on hierarchical CDMA architectures [3]- [8] but none contains an extensive study on soft handoff performance. In [6], the authors suggest a macrodiversity power control scheme which essentially places the entire system traffic in soft handoff mode. Such schemes increase the system performance at the expense of increased handoff signaling overhead and infrastructure cost.…”

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confidence: 99%

Soft handoff analysis for hierarchical CDMA cellular systems

Kim

Stuber²,

Chung³

IEEE VTS 53rd Vehicular Technology Conference, Spring 2001. Proceedings (Cat. No.01CH37202)

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Abstract-A new soft handoff analysis for hierarchical code-division multiple-access (CDMA) cellular systems is presented. Hierarchical cellular architectures have been proposed to increase cellular system capacity and flexibility. In order to extend such architectures to CDMA-based systems, the performance of soft handoff in hierarchical architectures must be considered. We first develop an analytical method for studying the interference in hierarchical CDMA cellular systems. We then apply the obtained results to a soft handoff analysis model to study the performance of soft handoff in hierarchical architectures. It is observed that dynamic handoff parameter assignment, where parameters are dynamically adjusted according to given interference conditions, offers a more efficient handoff mechanism than fixed handoff parameter assignment.Index Terms-Active set, carrier-to-interference ratio (CIR), code-division multiple access (CDMA), hierarchical architectures, macrocell, microcell, soft handoff.

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Macrodiversity power control in hierarchical CDMA cellular systems

Cited by 21 publications

References 18 publications

Comparison of Downlink Power Allocation Mechanisms in Soft Handoff for the WCDMA System with Heterogeneous Cell Structures

Comparison of Downlink Power Allocation Mechanisms in Soft Handoff for the WCDMA System with Heterogeneous Cell Structures

Non-real time packet transmission for a microcell (hotspot) embedded in CDMA macrocell systems

Soft handoff analysis for hierarchical CDMA cellular systems

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