Resource Allocation in a Cellular CDMA Environment (original) (raw)
Related papers
Effective bandwidth-based admission control for multiservice CDMA cellular networks
IEEE Transactions on Vehicular Technology, 1999
In this paper we develop product form tra c models for single and multiple cell CDMA networks with multiple classes of mobile subscriber. The key feature of this development is the speci cation of a exible call admission control procedure that details the numbers of mobiles of each class in each cell that the system operator should allow in order to maintain an acceptable quality of service. E ective bandwidth techniques from the analysis of statistical multiplexing at an ATM-based broadband ISDN link are used to give performance guarantees that overcome the variability in interference levels characteristic of CDMA cellular networks. The result is an admissible region bounded by a nite number of hyperplanes and a simple, e cient, call admission policy.
On multi-cell admission control in CDMA networks
International Journal of Communication Systems, 2008
We consider a multi-cell (MC) code division multiple access (CDMA) system that supports multiple service classes, including peak rate allocated and elastic ones. Peak rate allocated sessions-when admitted into the system-transmit at a constant bit rate, while elastic sessions can be slowed down at the expense of increasing their residency time. Admitted sessions cause an instantaneous bit rate-dependent interference in neighbour cells. In this rather general setting, we propose a method to calculate the class-wise blocking probabilities as the functions of the estimated so-called inter-cell coupling factors. In the paper this coupling factor is the ratio between the uplink path gains to different Node-B:s (that can be easily obtained in a CDMA system from pilot measurement reports), but our model could include other coupling measures as well. We find that when these coupling factors are underestimated, the system may get into false states (FSs) or false rate states (FRSs) that lead to violating the noise rise threshold. As traffic becomes increasingly elastic, the probability of FSs decreases, but the probability of FRSs increases. Based on numerical results, we make the point that as the traffic becomes more elastic, avoiding the underestimation of these coupling factors as well as exercising MC admission control plays an increasingly important role in guaranteeing proper service quality. 26 G. FODOR AND M. LINDSTRÖM increases [1]. (See also [2] and a refined model in [3].) This result is non-trivial, since decreasing the GBR leads to increasing the holding time of the elastic sessions.
Capacity Design and Performance of Call Admission Control in Cellular CDMA Systems
IEEE Journal on Selected Areas in Communications, 1997
Since code-division multiple-access (CDMA) capacity is interference limited, call admission control (CAC) must guarantee both a grade of service (GoS), i.e., the blocking rate, and a quality of service (QoS), i.e., the loss probability of communication quality. This paper describes the development of a new capacity design method based on these two concepts. Theoretical expressions for GoS and QoS as functions of traffic intensity and CAC thresholds are first derived from the traffic theory viewpoint, and then a design method using these expressions is presented. At that time, two strategies for CAC are assumed. One is based on the number of users, and the other is based on the interference level. Computer simulation results are presented that strongly support the proposed design method. Furthermore, numerical examples and a performance comparison of the two strategies considering various propagation parameters, nonuniform traffic distributions, and various transmission rates are shown
Resource allocation in multi-cell CDMA communication systems
IEEE International Conference on Communications, 2003. ICC '03., 2003
In a multimedia code division multiple access (CDMA) system, the network performance depends on the success and efficiency in allocating system resources. The system resources in terms of bandwidth and power should be efficiently distributed to each mobile to guarantee its quality of service (QoS) requirements. In this paper, we propose a received power limited (RPL) power assignment, so that the fair packet loss sharing (FPLS) scheduling can be implemented in the multi-cell resource allocation. The basic idea of FPLS is to schedule the transmission of multimedia packets in such a way that all the users have a fair share of packet loss according to their QoS requirements, which maximizes the number of the served users under the QoS constraints. The RPL minimizes the received power for each packet. With known path loss, it in turn minimizes the transmitted power as well. The intercell interference caused by the scheduled packets is also limited by the scheduling to increase the system capacity.
A call admission control scheme for packet data in CDMA cellular communications
IEEE Transactions on Wireless Communications, 2000
In a wireless multimedia code division multiple access (CDMA) system, the resources in terms of transmission rate and power should be efficiently distributed to each user to guarantee its quality-of-service (QoS) requirements. In this paper, a resource allocation algorithm which combines packet scheduling and power assignment is proposed to achieve efficient resource utilization under QoS constraints. The packet scheduling is based on the fair packet loss sharing (FPLS) principle, and the power assignment is determined by the received power limited (RPL) scheme. The basic idea of FPLS is to schedule the transmission of multimedia packets in such a way that all the users have a fair share of packet loss according to their QoS requirements, which maximizes the number of the served users with QoS satisfaction. The RPL scheme minimizes the received power for each packet. Given the propagation path loss, it in turn minimizes the transmitted power as well. The intercell interference from the scheduled packets is also limited in order to increase the system capacity.
2003
Abstract A dynamic call admission control and resource reservation scheme suitable for CDMA systems is proposed. Preferential treatment is given to high priority calls by preserving an interference guard margin (IGM), which is dynamically adjusted by referencing traffic conditions in neighboring cells based upon users' quality of service. A comprehensive service model is used including users' service rates, priority levels, mobility and rate adaptivity.
Interference-based capacity analysis in CDMA cellular systems
2003 IEEE Wireless Communications and Networking, 2003. WCNC 2003.
In multiple cellular CDMA systems, the channel capacity heavily depends upon the interference caused by the signal power of other users. In this paper, we exactly quantify the cell capacity by focusing on not only the number of users but also the location of active users. To inspect the effect of multicell CDMA environments, we model three 1/6 cells divided by 60 • sector antennas and analyze the increased interference when a user is added to the unit of cell. Based on the capacity analysis, we propose a new call admission control scheme that uses the location information of users. Whenever a new user arrives, our scheme checks whether the admittance of that user can occur within the cell capacity. If the user is far away from the base station, it will have less chance of acceptance because it creates more interference, resulting in reduced capacity. Our scheme allows more users to enter the network if they generate less interference. Therefore it has the effect of increased system capacity without sacrificing the QoS of all the other active users. Through simulations we show that the performance is improved by 10 to 20% in terms of the number of active users that can be accomodated.
Capacity and Quality Optimization of CDMA Networks
2009
Coverage and capacity are important issues in the planning process for cellular third generation (3G) mobile networks. The planning process aims to allow the maximum number of users sending and receiving adequate signal strength in a cell. This paper describes the conceptual expressions require for network coverage and capacity optimization analysis, examines service quality issues, and presents practical solutions to problems common to sub-optimality of CDMA networks.
Admission Control for Maximal Throughput in CDMA Systems
2004
Power control is a fundamental component of CDMA networks because of the interference that users cause to one another. Consequently, too many users in the system may lead to an overload whereas too few would generate an inefficient use of resources. Previous work by the authors has highlighted some fundamental properties of a CDMA system pertaining to the required power distribution when a particular terminal has reached its power limit. These properties have formed the basis for an admission control scheme which leads to an efficient use of system resources. This paper expands on this scheme and shows that optimal throughput with a fixed number of users can be achieved for a range of received power values and that this range of values is affected by the geometry of the users’ location relative to the base station. Further, we determine the conditions under which both the analytical solutions and physical simulations agree.