Hybrid OVSF code assignment scheme in W-CDMA

Sekine, Yoshitaka; Kawanishi, Ken’ichi; Yamamoto, Ushio; Onozato, Yoshikuni

doi:10.1109/pacrim.2003.1235797

Cited by 10 publications

(8 citation statements)

References 3 publications

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“…HCA [4] firstly carry out RDA and in the case of blocking a local DCA is carried out as explained in the flow chart of Fig. 6.…”

Section: F Hybrid Code Allocation (Hca)mentioning

confidence: 99%

An Improved OVSF Code Assignment Scheme at the Forward Link of WCDMA 3G System

Bakura¹,

Jing²,

Sun³

2012

IJMLC

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Abstract-CDMA is the access technique adopted in the third generation wireless system. In this technique, all users share the same bandwidth simultaneously but with different codes. This sharing generates interferences that can reduce the overall throughput of the WCDMA network when using a weak code allocation algorithm. In this paper we propose a code management and allocation scheme that ensures to a great extend an unrestricted access to the Wideband Code Division Multiple Access (WCDMA) network and greatly reducing the fragmentation of the code tree. Rather than simply keeping the code tree as compact as possible by merely depending on the request rate, we design an improved Region Division Allocation (IRDA) of OVSF codes a scheme for OVSF code tree management for the universal mobile telecommunication system (UMTS) by considering characteristics of traffic and dynamic resource allocation (DRA) to make the management efficient and satisfy different quality-of-service (QoS) requirements requested by diverse multimedia. According to our proposal, users would not only be restricted to their pre-defined code region but are allowed to borrow from other code regions and return to their home code if released by initial users. The simulation result indicates that optimum and fair usage of the available code was achieved

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“…HCA [4] firstly carry out RDA and in the case of blocking a local DCA is carried out as explained in the flow chart of Fig. 6.…”

Section: F Hybrid Code Allocation (Hca)mentioning

confidence: 99%

An Improved OVSF Code Assignment Scheme at the Forward Link of WCDMA 3G System

Bakura¹,

Jing²,

Sun³

2012

IJMLC

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“…As an example, for a newly arrived data packet seeing the code tree of Fig. 2, the candidate code set is found to be S = { (3,5), (4,5), (4,9), (4,10), (4,11), (4,14)}. If the mobile terminal is two-code capable, the base station will assign two candidate codes to carry the transmission of this data packet.…”

Section: Compact Code Assignmentmentioning

confidence: 99%

“…2005.858166 have better performance at the expense of higher computational complexity. Many single-code rearrangeable code assignment schemes were proposed in literature [4]- [14]. Among them, the priority issue between realtime traffic and best-effort traffic was considered in [4], [7] and [9].…”

Section: Introductionmentioning

confidence: 99%

Multicode Multirate Compact Assignment of OVSF Codes for QoS Differentiated Terminals

Yang¹,

Yum

2005

IEEE Trans. Veh. Technol.

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Orthogonal variable spreading factor (OVSF) codes are used in both universal terrestrial radio access-frequency division duplex (UTRA-FDD) and time division duplex (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 different quality of service (QoS) requirements. Priority differentiation between multirate realtime traffic and best-effort data traffic is also supported in MMCA. Analytical and simulation results show that MMCA is efficient and fair. Index Terms-Dynamic channel assignment (DCA), orthogonal variable spreading factor (OVSF) code, quality of service (QoS), universal terrestrial radio access (UTRA).

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“…Therefore, the OVSF code tree has a limited number of available codes (limited code capacity). Many code assignment algorithms were proposed for CDMA . Recently, we proposed a new adaptive code assignment algorithm, which could minimize the code blocking probability due to the code capacity limitation .…”

Section: Introductionmentioning

confidence: 99%

Combined code reuse scheme with two‐dimensional OVSF codes assignment algorithm for uplink multi‐user/multi‐rate block spread multi‐cellular CDMA

Meng

Adachi

2012

Wireless Communications

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The two‐dimensional (2D) block spread code division multiple access (CDMA) can avoid the uplink multiple‐access interference with low‐complexity single‐user detection in a slow fading channel and, therefore, is very attractive. In the 2D spreading, orthogonal variable spreading factor (OVSF) is used for spreading; an important problem is how to efficiently assign the limited resource of OVSF codes to users with different data rates, while meeting the requirement of quality of service in a multi‐cell environment. In this paper, it is shown that the code reuse can improve the code reuse efficiency and the proposed code reuse scheme combined with code assignment algorithm can allow flexible multi‐rate uplink transmission. The computer simulation confirms that the proposed code assignment algorithm improves the code reuse efficiency while achieving lower blocking probability than traditional CDMA. Copyright © 2012 John Wiley & Sons, Ltd.

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Hybrid OVSF code assignment scheme in W-CDMA

Cited by 10 publications

References 3 publications

An Improved OVSF Code Assignment Scheme at the Forward Link of WCDMA 3G System

An Improved OVSF Code Assignment Scheme at the Forward Link of WCDMA 3G System

Multicode Multirate Compact Assignment of OVSF Codes for QoS Differentiated Terminals

Combined code reuse scheme with two‐dimensional OVSF codes assignment algorithm for uplink multi‐user/multi‐rate block spread multi‐cellular CDMA

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