The capacity of a spread spectrum CDMA system for cellular mobile radio with consideration of system imperfections

Newson, P.; Heath, Martlesham

doi:10.1109/49.286674

Cited by 82 publications

(26 citation statements)

References 12 publications

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“…Let , where is a constant that can be determined from the path loss exponent, shadowing parameters and geometric size of the uniform cellular networks. Some typical values of have been given by analysis and simulation in [25]. Substituting by into (8), we have (26) Neglecting the thermal noise power , we have…”

Section: Numerical Resultsmentioning

confidence: 99%

“…The weight of each best-effort data flow is . Simulation results for the heterogeneous traffic are summarized in Table I, where theoretical delay bounds obtained from (25) for real-time traffic are also given for comparison. It can be seen that, with the weighted fair scheduling by CDGPS and C-CDGPS, the real-time traffic flows, voice and video, can achieve lower packet delays than the delay-insensitive Poisson data traffic.…”

Section: Numerical Resultsmentioning

confidence: 99%

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Dynamic Fair Scheduling With QoS Constraints in Multimedia Wideband CDMA Cellular Networks

Shen

Mark

2004

IEEE Trans. Wireless Commun.

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Abstract-A class of dynamic fair scheduling schemes based on the generalized processor sharing (GPS) fair service discipline, under the generic name code-division GPS (CDGPS), is proposed for a wideband direct-sequence code-division multiple-access (CDMA) cellular network to support multimedia traffic. The CDGPS scheduler makes use of both the traffic characteristics in the link layer and the adaptivity of the wideband CDMA physical layer to perform fair scheduling on a time-slot by time-slot basis, by using a dynamic rate-scheduling approach rather than the conventional time-scheduling approach. Soft uplink capacity is characterized for designing efficient CDGPS resource allocation procedure. A credit-based CDGPS (C-CDGPS) scheme is proposed to further improve the utilization of the soft capacity by trading off the short-term fairness. Theoretical analysis shows that, with the C-CDGPS scheme, tight delay bounds can be provided to delay-sensitive traffic, and short-term unfairness can be bounded so that long-term weighted fairness for all users can still be satisfied. Simulation results show that bounded delays, increased throughput, and long-term fairness can be achieved for both homogeneous and heterogeneous traffic.Index Terms-Code-division multiple-access (CDMA), creditbased scheduling, dynamic fair scheduling, generalized processor sharing (GPS), quality-of-service (QoS), soft capacity.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Numerical Resultsmentioning

confidence: 99%

Dynamic Fair Scheduling With QoS Constraints in Multimedia Wideband CDMA Cellular Networks

Shen

Mark

2004

IEEE Trans. Wireless Commun.

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“…We will use these maps in this study. 4 -The signal power of each diversity branch alone has too high a variance to maintain signal quality, but the combined signal has a lower variance and is able to meet quality requirements.…”

Section: P I # Mmentioning

confidence: 98%

Performance of a fixed‐beam system in the is‐95 CDMA forward link

Moorti¹,

Paulraj²,

Stützle³

1998

Trans Emerging Tel Tech

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Abstract. We study the performance of a fixed-beam system in the forward link of IS-95 CDMA systems by means of Monte Carlo simulations. The simulations are performed using a comprehensive model of the forward link which includes correlated shadowing, soft and softer handoff. and transmit power allocation. The effects of user distribution, softlsofter handoff threshold, and multipath diversity are examined. We find that the availability of signal diversity plays an important role in the system performance. When the soft handoff threshold is decreased from -12 dB to -18 dB. capacity increases by 15%. but handoff overhead more than doubles. When fifty percent of users have 2-ray multipath. capacity increases by 18%. Thus, the availability of multipath in the system has a dramatic influence on forward link capacity. A non-uniform distribution using a "highways" model reduces capacity by more than a half. This shows that for successful implementation of a fixed-beam system, it is important to plan cell sites in a way that keeps loading uniformly distributed in azimuth.

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“…First, Ψ i (h, ν) is approximated by its average. As observed in [12], taking the average of the MAI to compute the outage probability corresponds to considering that the fluctuations of the MAI term may have a variance that is small when compared to the variance of the user signal power. Second, the product between exp(ξ i ) and z i in the SINR expression can be approximated by a lognormal variable exp(ξ i ) as proposed in [9, pag.…”

Section: Outage Probability Approximationmentioning

confidence: 99%

Outage-Based Rate Maximization in CDMA Wireless Networks

d’Angelo

Fischione

Butussi

et al. 2008

IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference

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Abstract-The problem of maximizing the sum of the transmit rates while limiting the outage probability below an appropriate threshold is investigated for networks where the nodes have limited processing capabilities. We focus on CDMA wireless network whose rates are characterized under mixed Rayleighlognormal fading. The outage probability is given implicitly by a complex function so that solving the optimization problem requires substantial computing. In this paper, we propose a novel explicit approximation of this function that allows solving the problem in an affordable manner. We propose two solutions of the maximization problem with the simplified outage probability constraint: one solves the problem using mixed integer-real programming. The other relaxes the constraints that rates be integers yielding a standard convex programming optimization that can be solved much faster. Numerical results show that our approaches perform well for average values of the outage requirements.

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The capacity of a spread spectrum CDMA system for cellular mobile radio with consideration of system imperfections

Cited by 82 publications

References 12 publications

Dynamic Fair Scheduling With QoS Constraints in Multimedia Wideband CDMA Cellular Networks

Dynamic Fair Scheduling With QoS Constraints in Multimedia Wideband CDMA Cellular Networks

Performance of a fixed‐beam system in the is‐95 CDMA forward link

Outage-Based Rate Maximization in CDMA Wireless Networks

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