. The paper presents a new cellular architecture for radio access, CDPA, that can be applied to present and future cellular systems, independently of the cell size. It poses as an appealing alternative to systems based on classical bandwidthsubdivision methods, namely TDMA, FDMA or CDMA. In these systems, parallelism of communications is achieved by subdividing the bandwidth "a priori" among cells. In CDPA no bandwidth subdivision is operated. All cells and terminals use a single frequency channel and transmit packets on a slotted channel. Parallel transmission in different cells is achieved through the "capture" capability. A dynamic polling mechanism, C-PRMA, managed by the base station, guarantees almost immediate retransmission of packets that are not captured, thus assuring that packets are eventually correctly received . Analytical evaluations show that CDPA has the potential to provide larger capacity than the other cited systems in the case of continuous traffic sources. Furthe...

Recently, a new method for achieving spectrum reuse in cellular systems, called Capture-Division Packetized Access (CDPA), has been introduced. The method is based on packet switching and uses a single frequency in all cells, allowing each transmitter to access the full bandwidth. Practically, the CDPA's way of operation can be seen as an S-ALOHA scheme among different cells in which the Mobile Stations belonging to the same cell transmit using a collision-free mechanism, which is easily obtained due to the very short intra-cell propagation delay. Parallel transmission in different cells is achieved through the "capture" capability. Packets that are not captured are almost immediately retransmitted, thus assuring that packets are eventually correctly received. In this paper we analyze the capacity of the system in which two frequencies are used for the communications to and from the base stations. Analytical evaluations show that, although uplink and downlink channels behave differentl...

Cellular frequency reuse is known to be an efficient method to allow many wireless telephone subscribers to share the same frequency band. However, for wireless data and multi-media communications optimum cell layouts differ essentially from typical solutions for telephone systems. We argue that wireless radio systems for bursty message traffic preferably use the entire bandwidth in each cell. Packet queuing delays are derived for a network with multipath fading channels, shadowing, path loss and discontinuously transmitting base stations. Interference between cells can be reduced by appropriately scheduling transmissions or by `spatial collision resolution'.

. This paper focuses on a narrow band technical solution that uses decentralized spectrum sharing to facilitate open access among competing Personal Communications Services (PCS) operators. Existing policies that apportion spectrum by Fixed Channel Assignment (FCA) involve inefficiencies resulting from fragmentation of the available resource into mutually exclusive frequency blocks. Dynamic Channel Assignment (DCA) has been previously demonstrated to be flexible in handling traffic variability and to simplify frequency planning for a single network operator. In this paper we use a discrete event simulation to demonstrate that DCA with Autonomous Reuse Partitioning (ARP) provides more capacity than standard DCA; this property still holds when channels are shared among multiple operators, with partially overlapping networks and unequal traffic shares. We explore the impact of limiting the maximum number of channels that can be assigned to one cell site as an incentive for operators to bu...

In this paper the performance of a cellular mobile radio system with frequency reuse is evaluated, in terms of outage probability. Deterministic path loss, log-normal shadowing and Ricean fading are accounted for, and the use of diversity and power control is considered in order to enhance the system performance. Both hexagonal and lineal cells are considered. Particular attention is given to the sensitivity of the outage probability to the system parameters, especially those related to the propagation model (fading, shadowing and path loss). It is seen that diversity and power control can improve the system behavior. The performance is sensitive to the fading parameter (i.e., the Rice factor) of the intended user, but is relatively independent of that of the interferers; also, a significant dependence is observed on the shadowing parameter, whereas a limited dependence is seen on the outage threshold and on the channel utilization. Finally, the presence of a dual path loss law degrade...

Power control is an essential radio resource management method in CDMA cellular commu-nication systems, where co-channel interference is the primary capacity-limiting factor. Power control aims to control the transmission power levels in such a way that acceptable quality of service for the users is guaranteed with lowest possible transmission powers. All users benefit from the minimized interference and the preserved signal qualities. In this thesis new closed loop power control algorithms for CDMA cellular communication systems are proposed. To cope with the random changes of the radio channel and interference, adaptive algorithms are considered that utilize ideas from self-tuning control systems. The inher-ent loop delay associated with closed loop power control can be included in the design process, and thus alleviated with the proposed methods. Another problem in closed-loop power control is that extensive control signaling consumes radio resources, and thus the control feedback band-width must be limited. A new approach to enhance the performance of closed-loop power control in limited-feedback-case is presented, and power control algorithms based on the new approach are proposed.

The actual trend towards Personal Communication Systems suggests to devote considerable research efforts to find more efficient multiple access techniques in order to improve the system capacity. In this work we compare the system performance of three multiple access techniques used in mobile radio systems: TDMA, CDMA, and the slotted Aloha packet system. The performance of the three protocols has been evaluated in the presence or absence of both antenna diversity and power control, with focus on the base-to-mobile link. The results obtained show that CDMA and slotted Aloha work much better than TDMA; moreoverthe performance of slotted Aloha is comparable to CDMA, while exhibiting a virtual insensitivity to propagation conditions. I. INTRODUCTION Personal Communication Systems are expected to support a variety of multimedia services, e.g. high quality voice, data, facsimile, and e-mail transmission; these services are possible only if efficient multiple access techniques are provided...

We consider the average area spectral efficiency (ASE) of variable-rate transmission cellular mobile systems. This efficiency is defined as the sum of the maximum average data rates/Hz/unit area supported by a cell's base station. We study this efficiency as a function of the reuse distance for the uplink of FDMA and TDMA systems under different interference configurations. Results indicate that, based on the worst-case interference configuration, the optimal reuse distance is approximately four. However, this optimal reuse distance is two for the best-case and the average interference configurations (i.e. frequencies should be reused every cell). In addition, the ASE decreases as an exponential of a 4th order polynomial relative to the cell size. This result quantifies exactly how much cellular system capacity increases with decreased cell size. We also quantify the increase in ASE due to antenna sectorization. We conclude by analyzing the effect of traffic loading on the ASE when a f...

Abstract Cellular frequency reuse is known to be an efficient method to allow many wireless telephone subscribers to share the same frequency band. However, frequency reuse laeds to mutual interference among co-channel cells. We review the technique for computing and modelling link performance in cellular networks. 1

There is a singular dichotomy to writing a dissertation: it is an isolated endeavor, yet impossible without the support of family, friends, and colleagues. First of all, I would like to thank my family, for their unconditional love, support, and sacrifices. I would like to thank my father for teaching me the value of patience (with mild success), my mother for teaching me the value of spontaneity (with great success), and my sisters Shachi and Shruti for showering me with love, affection, and attention. They made me the person I am today. I would like to express my deepest gratitude towards my advisor Prof. Brian L. Evans. Prof. Evans has been a constant source of support and ideas; someone to talk to, rather than report to; guiding me to find my path, rather than directing me towards one. His intelligence, breadth of experience, and organizational ability are attributes that I can only hope to duplicate. I would like to thank my committee members Prof. Jeff Andrews, Prof. Robert Heath, Prof. Elmira Popova, and Prof. Haris Vikalo for their prying questions and invaluable comments. I would especially like to thank Prof. Andrews and Prof. Heath, whose classes have been a most enriching experience. I would also like to thank Prof. Surendra Prasad and Prof. Shiv Joshi for inspiring me to pursue signal processing and communications. I would like to thank my best friends from high school: Mayank Sharma, v Dr. Sahil Khera, Neha Sharma, Kabeer Chawla, and Mukund Kumar for showing me a life outside of studies; my best friends from IIT: Varun Agarwal, Chirag