Multiple Rake Combiners and Performance Improvement in 3G and Beyond WCDMA Systems

Saini, Davinder S.; Upadhyay, Manisha

doi:10.1109/tvt.2009.2015143

Cited by 31 publications

(14 citation statements)

References 15 publications

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“…A number of code assignment schemes have been proposed to reduce or even eliminate the wasted capacity. Flexible data services of different rates could be provided by an assignment of multiple orthogonal sequences to each user according to the data rate requested [72]. However, a multicode assignment requires each user to have multiple rake demodulators, each of which responds to a different sequence.…”

Section: Synchronous Communicationsmentioning

confidence: 99%

Principles of Spread-Spectrum Communication Systems

Torrieri¹

2015

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Section: Synchronous Communicationsmentioning

confidence: 99%

Principles of Spread-Spectrum Communication Systems

Torrieri¹

2015

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“…However, the VSF-OFCDM managed by an OVSF code tree needs an efficient algorithm to allocate codes to different arrival connections. The code allocation algorithms of the VSF-OFCDM scheme can be classified into three types: the allocations of 2D-based single code [13,14], single code [15][16][17][18][19][20][21], and multicode [22][23][24][25][26][27][28][29] for a single connection request.…”

Section: Related Studies Of Radio Resource Managementsmentioning

confidence: 99%

Adaptive radio resource management for maximizing reward and balancing loads in 4G hybrid universal mobile telecommunications system and long term evolution communications

Chang

Liang

Cao

2013

Wirel. Commun. Mob. Comput.

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The universal mobile telecommunications system (UMTS) and long term evolution (LTE)/LTE-advanced specifications have been proposed to offer high data rate for the forwarding link under high-mobility wireless communications. The keys include supporting multi-modes of various coding schemes (e.g., VSF-OFCDM, OFDM, OFDMA), multiple-input multiple-output, relay networks, and so on. To balance loads among different communication interfaces is one of the most important issues that should be addressed for achieving efficient radio resource allocations. In a shared packet service, the 3GPP UMTS adopts the VSF-OFCDM interface to allocate orthogonal codes of an OVSF code tree in two-dimension (2D) spreading at the time and frequency domains. However, it easily leads to high packet loss rate and high bandwidth waste rate, because it does not consider interference and the adaptive modulation and coding scheme simultaneously. Conversely, although the LTE/LTE-advanced interface offers a high data rate, it suffers from unbalanced loads and moderate reward. This paper thus proposes an adaptive radio resource allocation for balancing loads between the UMTS and LTE/LTE-advanced interfaces according to various interference and mobility environments. In addition, an adaptive multicode allocation is proposed for the UMTS to minimize the bandwidth waste rate while guaranteeing quality of service. Numerical results indicate that the proposed approach outperforms other approaches in fractional reward loss and system utilization.

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“…It may cause rate wastage and a code fragmentation problem. The multicode design [10] gives the optimum number of codes/rakes to handle quantized and nonquantized calls. Leftmost code assignment (LCA) [6], crowded first assignment (CFA) [6], dynamic code assignment (DCA) [3] and fixed-set partitioning (FSP) [7] are some of the single code assignment schemes.…”

Section: Existing Ovsf Code Assignment Designsmentioning

confidence: 99%

“…The multirate multicode compact assignment [9] scheme uses the concept of compact index to accommodate users with differentiated QoS requirements. The multicode design [10] gives the optimum number of codes/rakes to handle quantized and nonquantized calls. The DCA-Call Admission Control (CAC) scheme discussed in [11] reduces the complexity of the DCA scheme with similar throughput performance.…”

Section: Existing Ovsf Code Assignment Designsmentioning

confidence: 99%

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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Multiple Rake Combiners and Performance Improvement in 3G and Beyond WCDMA Systems

Cited by 31 publications

References 15 publications

Principles of Spread-Spectrum Communication Systems

Principles of Spread-Spectrum Communication Systems

Adaptive radio resource management for maximizing reward and balancing loads in 4G hybrid universal mobile telecommunications system and long term evolution communications

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

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