An OVSF code assignment scheme utilizing multiple RAKE combiners for W-CDMA

Yen, Li-Hsing; Tsou, Ming-Chun

doi:10.1016/j.comcom.2004.05.009

Cited by 15 publications

(9 citation statements)

References 10 publications

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“…By using this criterion, the proposed Compact Assignment (CA) scheme can offer comparable performance to rearrangeable schemes. Multicode rearrangeable code assignment schemes were proposed in [15,16] for uniform mobile terminals having exactly the same capability in supporting multicode transmission, and in [17,18] for different multicode capable terminals. All these multicode schemes consider only multirate realtime traffic class.…”

Section: Introductionmentioning

confidence: 99%

Multicode Multirate Compact Assignment of OVSF Codes for QoS Differentiated Terminals

Yang

Yum

2004

Personal Wireless Communications

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Abstract. Orthogonal Variable Spreading Factor (OVSF) codes are used in both UTRA-FDD and UTRA-TDD of the third-generation (3G) mobile communication systems. They can support multirate transmissions for mobile terminals with multicode transmission capabilities. In this paper, a new OVSF code assignment scheme, namely "Multicode Multirate Compact Assignment" (MMCA), is proposed and analyzed. The design of MMCA is based on the concept of "compact index" and takes into consideration mobile terminals with different multicode transmission capabilities and Quality of Service (QoS) requirements. Specifically, priority differentiation between multirate realtime traffic and besteffort data traffic is supported in MMCA. Analytical and simulation results show that MMCA is efficient and fair.

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Section: Introductionmentioning

confidence: 99%

Multicode Multirate Compact Assignment of OVSF Codes for QoS Differentiated Terminals

Yang

Yum

2004

Personal Wireless Communications

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“…We now evaluate the performance of the proposed schemes against the multi-code assignment schemes presented in [6]. In the following, the performance of [6] is denoted by YT04-LM and YT04-CF, where LM=left-most and CF=crowded-first.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…In the following, the performance of [6] is denoted by YT04-LM and YT04-CF, where LM=left-most and CF=crowded-first. Firstly, we measure the blocking probability for each scheme.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…Moreover, the code placement and replacement are not taken into consideration. To prevent redundant computation, the scheme proposed in [6] uses the technique of dynamic programming scheme to build up a multi-code table in advance so that less time in selecting the best multi-code is required. In [7], the internal and external fragmentation problems are defined and solved by using multicodes.…”

Section: Introductionmentioning

confidence: 99%

“…In the literature, there are two assignment approaches for OVSF codes: single-code [2], [3], [4] and multi-code [5], [6], [7]. Single-code assignment allocates only one code to a user.…”

Section: Introductionmentioning

confidence: 99%

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An OVSF code tree partition policy for WCDMA systems based on the multi-code approach

Ferng

Chin

Shiung³

et al.

VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005.

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Abstract-Orthogonal variable spreading factor (OVSF) codes for wide-band CDMA (WCDMA) systems have been proposed in the third generation (3G) mobile communications' standard to support services of variable rates. To assign OVSF codes, there are single-code and multi-code approaches. In this paper, the multi-code placement and replacement issue is addressed. We propose a tree partition policy for managing the OVSF code tree to reduce code fragments and the number of code reassignments. Besides, we adjust the multi-code rate according to a unit-based method, which is capable of decreasing the number of code fragments because fewer low-rate codes are utilized. Through extensive simulations, it turns out that the tree partition policy and the unit-based multi-code method jointly perform better than the left-most and crowded-first schemes.

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Reducing code wastage in orthogonal variable spreading factor‐based wideband code division multiple access networks

Saini

Gupta

Joshi

2011

Int J Communication

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Most third-generation and beyond wideband code division multiple access networks use the orthogonal variable spreading factor code tree for channelization codes. The codes in this code tree are limited and the performance of a wireless network depends upon the code assignment for new calls. In this paper, we introduce a term called 'wastage capacity', which gives us the amount of wastage caused when a code (single or multiple) with a data rate higher than the rate of the incoming call is assigned to it. We suggest two methods to keep wastage capacity below an arbitrary threshold value or zero. In the first method, we devised an algorithm in which wastage up to a certain threshold would be tolerated and the minimum rakes to get this wastage capacity were identified. In the second approach, we reduced the wastage capacity to zero irrespective of the number of rakes at the expense of higher cost and complexity.

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An OVSF code assignment scheme utilizing multiple RAKE combiners for W-CDMA

Cited by 15 publications

References 10 publications

Multicode Multirate Compact Assignment of OVSF Codes for QoS Differentiated Terminals

Multicode Multirate Compact Assignment of OVSF Codes for QoS Differentiated Terminals

An OVSF code tree partition policy for WCDMA systems based on the multi-code approach

Reducing code wastage in orthogonal variable spreading factor‐based wideband code division multiple access networks

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