Multiservice/multirate pure CDMA for mobile communications

Azad, Hamid Sarbazi; Aghvami, A.H.; Chambers, W.C.

doi:10.1109/25.790513

Cited by 10 publications

(7 citation statements)

References 4 publications

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“…The performance of a multi-service/multirate pure CDMA network is evaluated in [3], in which the multiuser interference statistics are derived for both Gaussian and Rayleigh fading channels. Two service levels (low-and high-bit rates) are defined and the systems using different modulation schemes are compared.…”

Section: Related Workmentioning

confidence: 99%

Utility based service differentiation in CDMA data networks

Lin¹,

Chatterjee

Das

2006

Wireless Netw

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The wireless data services are getting more and more competitive because of the presence of multiple service providers, all of whom offer some relative advantages and flexibilities over the others. As a result, the user churn behavior (i.e., migration from one service provider to another) is causing tremendous revenue loss for the service providers and also failure of existing resource management algorithms to fully capture the impact of churning. Moreover, the quality of service (QoS) offered to users belonging to different classes calls for new resource management schemes that address the issues related to differentiated services.In this paper, we propose a framework to study the impact of user churn behavior on the resource management algorithms to provide class-based differentiated services in CDMA data networks. In particular, our framework incorporates the user churning behavior into the admission control and power management algorithms, so that the service provider's revenue loss due to churn can be minimized. Since optimal rate/power allocation in multi-rate CDMA systems is in general NP-Complete, we provide heuristics that try H. Lin ( ) Wireless Core Systems Engineering, Nortel, to provide solutions to the resource allocation problem in real-time. In our proposed framework, we add another layer of power management called Class-Based Power Allocation/Reduction (CBPAR) function, which works with the rate control algorithm to achieve power allocation. With CBPAR, the number of variables of the optimization problem is significantly reduced helping achieve the results in real-time. Our simulation study shows that the service provider's revenue can be improved with the help of CBPAR framework. It also reveals the relationship between users' sensitivity and tolerance to QoS degradation and optimal power allocations.

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Section: Related Workmentioning

confidence: 99%

Utility based service differentiation in CDMA data networks

Lin¹,

Chatterjee

Das

2006

Wireless Netw

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“…We are concerned with the transmissions of a single user and treat the other users as MAI. For sufficiently large number of users in the cell the central limit theorem (CLT) [14, p. 278] can be invoked to show that the MAI within the cell is Gaussian-distributed [15], [16].…”

Section: System Overviewmentioning

confidence: 99%

Adaptive Resource Allocation for Spectral Efficiency Maximization in Uplink WCDMA

Zarringhalam

Shikh-Bahaei

Charbit

2006

2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications

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In this contribution we examine the joint optimization of the outer-loop power control (OLPC) and spreading factor in order to improve the spectral efficiency in the uplink of wideband code-division multiple-access (WCDMA) systems, in the presence of additive white Gaussian noise (AWGN) and multiple access interference (MAI), and while maintaining an average transmit power constraint. The variable spreading factors (VSF) and the target signal-to-noise ratio (SNR) -set by the OLPC-are adapted according to the interference-to-noise ratio (INR) and the target instantaneous bit error rate (BER). We use the standardized Orthogonal VSF (OVSF) codes used for the uplink dedicated physical data channel (UL-DPDCH) and evaluate the performance over Nakagami flat fading channels. It is shown that the proposed scheme improves the spectral efficiency compared to systems that use constant spreading factor and OLPC, for a wide range of practical SNRs and signal-tointerference ratios (SIRs).

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“…(12)] as (4) where is the instantaneous power of the desired signal (in a Nakagami-fading channel, is the instantaneous received power of the th interferer (in a Nakagami-fading channel), is the bit period, is the one-sided power density of additive white Gaussian noise, is the processing gain of OVSF spreading code (i.e., ), is the instantaneous received for the desired signal, is the instantaneous received for the th interferer, and is the total number of packets involved in the multipacket collision. Note that (4) includes the additional factors (for the spread-spectrum processing gain) and 1/3 (for the asynchronous interference signal cross-correlation ratio), as described in [6].…”

Section: A Ra Packet Sinr With Single Antennamentioning

confidence: 99%

Performance analysis of slotted random access channels for W-CDMA systems in Nakagami fading channels

Cooper

Zeidler

McLaughlin

2002

IEEE Trans. Veh. Technol.

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We perform a new analysis of the performance of the wide-band code-division multiple access (W-CDMA) randomized slotted-offset random access channel with Nakagami-fading and compare it with the performance of a comparable randomized slotted-ALOHA-based random access channel. In a previous paper, it was shown through simulations that the W-CDMA random access channel is fast, robust, and simple to implement. However, the paper assumed that any random access packet arrival events involving multiple packets from cochannel mobile stations would result in lost packets. In this paper, closed-form equations are developed for the collision process of the arriving random access packets in slotted-offset and slotted-ALOHA random access channels. An analysis is then developed of the signal-to-interference and noise ratio of a packet involved in a multipacket direct-sequence code-division multiple-access collision with a generalized Nakagami fading channel and diversity reception at the base station. Finally, a closed-form equation is developed for the bit error rate and packet throughput of the slotted-offset-and slotted-ALOHA-based random-access channels. The results of the analysis show that considerable improvement in the random-access channel performance can be achieved when multiple arrival collisions, on the same timeslot and with the same signature code, are partially resolved. The results also show the random-access channel's sensitivity to fading severity, packet , spreading gain, and number of base station receive selection diversity antennas. Finally, it is shown that the W-CDMA random-access channel performs as well as comparable randomized Slotted-ALOHA designs in light fading conditions and slightly worse than Slotted-ALOHA in severe fading conditions. Index Terms-Nakagami fading channel, random access, slotted-ALOHA (S-ALOHA), wide-band code-division multiple access (W-CDMA). I. INTRODUCTION T HIS paper investigates the problem of random-access (RA) channel performance as it pertains to future wide-band code-division multiple-access (W-CDMA) wireless systems. Current cellular and PCS systems often suffer from reverse control channel (RCCH) contention and subsequent

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Multiservice/multirate pure CDMA for mobile communications

Cited by 10 publications

References 4 publications

Utility based service differentiation in CDMA data networks

Utility based service differentiation in CDMA data networks

Adaptive Resource Allocation for Spectral Efficiency Maximization in Uplink WCDMA

Performance analysis of slotted random access channels for W-CDMA systems in Nakagami fading channels

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