Showing papers in "Wireless Networks in 1995"

Multicluster, mobile, multimedia radio network

Abstract: A multi-cluster, multi-hop packet radio network architecture for wireless adaptive mobile information systems is presented. The proposed network supports multimedia traffic and relies on both time division and code division access schemes. This radio network is not supported by a wired infrastructure as conventional cellular systems are. Thus, it can be instantly deployed in areas with no infrastructure at all. By using a distributed clustering algorithm, nodes are organized into clusters. The clusterheads act as local coordinators to resolve channel scheduling, perform power measurement/control, maintain time division frame synchronization, and enhance the spatial reuse of time slots and codes. Moreover, to guarantee bandwidth for real time traffic, the architecture supports virtual circuits and allocates bandwidth to circuits at call setup time. The network is scalable to large numbers of nodes, and can handle mobility. Simulation experiments evaluate the performance of the proposed scheme in static and mobile environments.

Improving reliable transport and handoff performance in cellular wireless networks

Abstract: TCP is a reliable transport protocol tuned to perform well in traditional networks where congestion is the primary cause of packet loss. However, networks with wireless links and mobile hosts incur significant losses due to bit-errors and hand-offs. This environment violates many of the assumptions made by TCP, causing degraded end-to-end performance. In this paper, we describe the additions and modifications to the standard Internet protocol stack (TCP/IP) to improve end-to-end reliable transport performance in mobile environments. The protocol changes are made to network-layer software at the base station and mobile host, and preserve the end-to-end semantics of TCP. One part of the modifications, called the snoop module, caches packets at the base station and performs local retransmissions across the wireless link to alleviate the problems caused by high bit-error rates. The second part is a routing protocol that enables low-latency handoff to occur with negligible data loss. We have implemented this new protocol stack on a wireless testbed. Our experiments show that this system is significantly more robust at dealing with unreliable wireless links than normal TCP; we have achieved throughput speedups of up to 20 times over regular TCP and handoff latencies over 10 times shorter than other mobile routing protocols.

Mobile users: to update or not to update?

Abstract: Tracking strategies for mobile users in wireless networks are studied. In order to save the cost of using the wireless links mobile users should not update their location whenever they cross boundaries of adjacent cells. This paper focuses on three natural strategies in which the mobile users make the decisions when and where to update: the time-based strategy, the number of movements-based strategy, and the distance-based strategy. We consider both memoryless movement patterns and movements with Markovian memory along a topology of cells arranged as a ring. We analyze the performance of each one of the three strategies under such movements, and show the performance differences between the strategies.

A distributed routing algorithm for mobile wireless networks

Abstract: We present a loop-free, distributed routing protocol for mobile packet radio networks. The protocol is intended for use in networks where the rate of topological change is not so fast as to make “flooding” the only possible routing method, but not so slow as to make one of the existing protocols for a nearly-static topology applicable. The routing algorithm adapts asynchronously in a distributed fashion to arbitrary changes in topology in the absence of global topological knowledge. The protocol's uniqueness stems from its ability to maintain source-initiated, loop-free multipath routing only to desired destinations with minimal overhead in a randomly varying topology. The protocol's performance, measured in terms of end-to-end packet delay and throughput, is compared with that of pure flooding and an alternative algorithm which is well-suited to the high-rate topological change environment envisioned here. For each protocol, emphasis is placed on examining how these performance measures vary as a function of the rate of topological changes, network topology, and message traffic level. The results indicate the new protocol generally outperforms the alternative protocol at all rates of change for heavy traffic conditions, whereas the opposite is true for light traffic. Both protocols significantly outperform flooding for all rates of change except at ultra-high rates where all algorithms collapse. The network topology, whether dense or sparsely connected, is not seen to be a major factor in the relative performance of the algorithms.

Minimizing the average cost of paging under delay constraints

Abstract: Efficient paging procedures help minimize the amount of bandwidth expended in locating a mobile unit. Given a probability distribution on user location, it is shown that the optimal paging strategy which minimizes the expected number of locations polled $E[L]$ is to query each location sequentially in order of decreasing probability. However, since sequential search over many locations may impose unacceptable polling delay, D, optimal paging subject to delay constraints is considered. It is shown that substantial reductions in E[L] can be had even after moderate constraints are imposed on acceptable D (i.e., D \leq 3). Since all methods of mobility management eventually reduce to considering a time-varying probability distribution on user location, this work should be applicable to a wide range of problems in the area. most notably those with additive cost structures.

Mobile user location update and paging under delay constraints

Abstract: Wireless personal communication networks (PCNs) consist of a fixed wireline network and a large number of mobile terminals. These terminals are free to travel within the PCN coverage area without service interruption. Each terminal periodically reports its location to the network by a process called location update. When a call for a specific terminal arrives, the network will determine the exact location of the destination terminal by a process called terminal paging. This paper introduces a mobile user location management mechanism that incorporates a distance based location update scheme and a selective paging mechanism that satisfies predefined delay requirements. An analytical model is developed which captures the mobility and call arrival pattern of a terminal. Given the respective costs for location update and terminal paging, the average total location update and terminal paging cost is determined. An iterative algorithm is then used to determine the optimal location update threshold distance that results in the minimum cost. Analytical results are also obtained to demonstrate the relative cost incurred by the proposed mechanism under various delay requirements.

AIRMAIL: a link-layer protocol for wireless networks

Abstract: This paper describes the design and performance of a link-layer protocol for indoor and outdoor wireless networks. The protocol is asymmetric to reduce the processing load at the mobile, reliability is established by a combination of automatic repeat request and forward error correction, and link-layer packets are transferred appropriately during handoffs. The protocol is named AIRMAIL (AsymmetrIc Reliable Mobile Access In Link-layer). The asymmetry is needed in the design because the mobile terminals have limited power and smaller processing capability than the base stations. The key ideas in the asymmetric protocol design consist of placing bulk of the intelligence in the base station as opposed to placing it symmetrically, in requiring the mobile terminal to combine several acknowledgments into a single acknowledgment to conserve power, and in designing the base stations to send periodic status messages, while making the acknowledgment from the mobile terminal event-driven. The asymmetry in the protocol design results in a one-third reduction of compiled code. The forward error correction technique incorporates three levels of channel coding which interact adaptively. The motivation for using a combination of forward error correction and link-layer retransmissions is to obtain better performance in terms of end-to-end throughput and latency by correcting errors in an unreliable wireless channel in addition to end-to-end correction rather than by correcting errors only by end-to-end retransmissions. The coding overhead is changed adaptively so that bandwidth expansion due to forward error correction is minimized. Integrity of the link during handoffs (in the face of mobility) is handled by window management and state transfer. The protocol has been implemented. Experimental performance results based on the implementation are presented.

An auxiliary user location strategy employing forwarding pointers to reduce network impacts of PCS

Abstract: We propose an auxiliary strategy, called per-user forwarding, for locating users who move from place to place while using Personal Communications Services (PCS). The forwarding strategy augments the basic location strategy proposed in existing standards such as GSM and IS-41, with the objective of reducing network signalling and database loads in exchange for increased CPU processing and memory costs. The key observation behind forwarding is that if users change PCS registration areas frequently but receive calls relatively infrequently, it should be possible to avoid registrations at the Home Location Register (HLR) database, by simply setting up a forwarding pointer from the previous Visitor Location Register (VLR). Calls to a given user will first query the user's HLR to determine the first VLR which the user was registered at, and then follow a chain of forwarding pointers to the user's current VLR. We use a reference PCS architecture and the notion of a user's call-to-mobility ratio (CMR) to quantify the costs and benefits of using forwarding and classes of users for whom it would be beneficial. We show that under a variety of assumptions forwarding is likely to yield significant net benefits in terms of reduced signalling network traffic and database loads for certain classes of users. For instance, under certain cost assumptions, for users with CMR <0.5, forwarding can result in 20-60\% savings over the basic strategy. This net benefit is due to the significant saving in location update compared to a penalty of moderately increased call setup times for the infrequent occasions when these users do receive calls.

Dynamic mobile user location update for wireless PCS networks

Abstract: The basic architecture of a personal communication network consists of a wireline network and mobile terminals. Each mobile terminal communicates with the wireline network through a nearby base station. In order to route incoming calls to a destination mobile terminal, the network must keep track of the location of each mobile terminal from time to time. This is achieved by location update such that each mobile terminal reports its current location to the network at specific time points. When an incoming call arrives, the network will page the mobile terminal starting from the last updated location. A trade-off, therefore, exists between the frequency of location update and the number of locations paged in order to track down the mobile terminal. This paper introduces a location update policy which minimizes the cost of mobile terminal location tracking. A mobile terminal dynamically determines when to update after moving to a new cell based on its mobility pattern and the incoming call arrival probability. The performance of this scheme is close to that of the optimal policy reported earlier. However, the processing time requirement of this scheme is very low. The minimal computation required by this scheme enables its usage in mobile terminals which has limited energy supply and computational power.

An efficient demand-assignment multiple access protocol for wireless packet (ATM) networks

Abstract: In a wireless packet (ATM) network that supports an integrated mix of multimedia traffic, the channel access protocol needs to be designed such that mobiles share the limited communications bandwidth in an efficient manner: maximizing the utilization of the frequency spectrum and minimizing the delay experienced by mobiles. In this paper, we propose and study an efficient demand-assignment channel access protocol, which we call Distributed-Queueing Request Update Multiple Access (DQRUMA). The protocol can be used for a wide range of applications and geographic distances. Mobiles need to send requests to the base station only for packets that arrive to an empty buffer. For packets that arrive to a non-empty buffer, transmission requests are placed collision-free by piggybacking the requests with packet transmissions. The simulation results show that even with the “worst possible” traffic characteristics, the delay-throughput performance of DQRUMA is close to the best possible with any access protocol. In addition, explicit slot-by-slot announcement of the “transmit permissions” gives the base station complete control over the order in which mobiles transmit their packets. This important feature helps the base station satisfy diverse Quality-of-Service (QoS) requirements in a wireless ATM network.

A wireless broadband ad-hoc ATM local-area network

Abstract: We describe the theory, design and ongoing prototyping of a wireless ATM LAN/PBX capable of supporting mobile users with multi-Mb/s access rates and multi-Gb/s aggregate capacities. Our proposed LAN consists of network nodes called Portable Base Stations (PBS) providing microcell coverage. The PBSs are designed to be low-cost, compact and high-speed and can be relocated conveniently. We employ a concept of ad-hoc networking in the layout of the PBS-to-PBS interconnection. That is, the PBSs can be distributed in an arbitrary topology to form a backbone network and can be reconfigured with relative ease. The PBS-to-PBS backbone links are high-speed (Gb/s) for supporting high system capacity. Although they can either be wired or wireless, our emphasis is on wireless implementations. The user-to-PBS links, on the other hand, are primarily for mobile access (e.g., 2-20 Mb/s) and therefore are wireless. Wired connections from stationary users to PBSs are also possible. Typical mobile users are assumed to be laptops or notebook computers. Services supported include conventional data applications (e.g., over TCP/IP or SPX/IPX) as well as multimedia (video, voice and data) applications with QoS (Quality-of-Service) guarantees. A “wireless ATM” concept is proposed so as to provide seamless internetworking with other wired ATM local and wide-area networks. Algorithms and control in our network are highly distributed for simple implementations and ease of mobility management. A new wireless VP/VC concept and a Homing Algorithm are described to provide ATM cell routing and connections in the network. PBS hardware and software architectures are discussed. Call management, network management and signaling are designed for simplicity, high performance and modular implementations. A fast network restoration scheme is proposed to cope with the potential link or node failures in the ad-hoc network. Error control is addressed taking the unreliable wireless links into consideration. Finally, a prototyping project called BAHAMA (Broadband Ad Hoc ATM Anywhere) for demonstrating this network concept is briefly outlined.

Scalable support for transparent mobile host internetworking

Abstract: This paper considers the problem of providing transparent support for very large numbers of mobile hosts within a large internetwork such as the Internet. The availability of powerful mobile computing devices and wireless networking products and services is increasing dramatically, but internetworking protocols such as IP used in the Internet do not currently support host movement. To address this need, the Internet Engineering Task Force (IETF) is currently developing protocols for mobile hosts in the Internet. This paper analyzes the problem to be solved, reviews the current state of that effort, and discusses its scalability to very large numbers of mobile hosts in a large internetwork.

Multicast security and its extension to a mobile environment

Abstract: Multicast is rapidly becoming an important mode of communication and a good platform for building group-oriented services. To be used for trusted communication, however, current multicast schemes must be supplemented by mechanisms for protecting traffic, controlling participation, and restricting access of unauthorized users to data exchanged by the participants. In this paper, we consider fundamental security issues in building a trusted multicast facility. We discuss techniques for group-based data encryption, authentication of participants, and preventing unauthorized transmissions and receptions. We also describe the application of these principles and techniques in designing an architecture for secure multicast in a mobile environment.

A preservation-based multicast (RBM) routing protocol for mobile networks: initial route construction phase

Abstract: We propose a combined multicast routing, resource reservation and admission control protocol, termed Reservation-Based Multicast (RBM), that borrows the “Rendez-vous Point” or “Core” concept from multicast routing algorithms proposed for the Internet, but which is intended for operation in mobile networks and routes hierarchically-encoded data streams based on user-specified fidelity requirements, real-time delivery thresholds and prevailing network bandwidth constraints. The protocol exhibits the fully distributed operation and receiver-initiated orientation of these proposed algorithms; but, unlike them, the protocol is tightly coupled to a class of underlying, distributed, unicast routing protocols thereby facilitating operation in a dynamic topology. This paper focuses on the initial route construction phase, assumed to occur during a static “snapshot” of the dynamic topology, and is therefore applicable to fixed networks as well, e.g. the Internet.

On the distribution of cumulated interference power in Rayleigh fading channels

Abstract: This paper deals with the distribution of cumulated instantaneous interference power in a Rayleigh fading channel for an infinite number of interfering stations, where each station transmits with a certain probability, independently of all others. If all distances are known, a necessary and sufficient condition is given for the corresponding distribution to be nondefective. Explicit formulae of density and distribution functions are obtained in the interesting special case that interfering stations are located on a linear grid. Moreover, the Laplace transform of cumulated power is investigated when the positions of stations follow a one- or two-dimensional Poisson process. It turns out that the corresponding distribution is defective for the two-dimensional models.

Using DHCP with computers that move0

Abstract: The Dynamic Host Configuration Protocol (DHCP) was designed to allow the frequent allocation of resources and configuration information useful to Internet hosts at boot time, including Internet addresses in particular. It turns out that getting a new Internet address is crucial to the problem of enabling the movement of Internet hosts from one network to another, and thus DHCP is quite relevant to the problem of providing seamless, transparent mobility to Internet hosts. We decided to investigate the ways that DHCP could be of assistance in this regard. Since the DHCP protocol was not itself designed for the purpose of providing host mobility, a number of problems arise. Our experience with deploying DHCP, and our proposed mechanisms for the use of DHCP with mobile computers, are the subjects of this paper.

Economic aspects of configuring cellular networks

Abstract: This paper addresses economic aspects of configuring cellular networks. Major components of costs and revenues and the major stakeholders are identified and a model is developed to determine the system configuration (e.g. cell size, number of channels, etc.) which will maximize the annual expected net revenues to the system operator. Key properties relating the various parameters of interest are derived. The results of computational experiments are presented and their implications are discussed. The computational results show that the optimal net revenue curves have a saw-tooth structure with two types of teeth; Large ones that come from switching between cellular technologies, and smaller jumps come the discretenes of base stations. The importance of capturing a high fraction of potential users, in early stages of cellular system introduction is investigated. Finally, the cost of competition and its implications for the regulatory agency and the cellular service providers are analyzed. It is shown that by dividing the available frequency spectrum between too many system operators, the overall value of the cellular system is reduced when compared to an approach which uses division of the overall service area into a larger number of service areas, each with only two system operatos. The above results have profound implications on public policies for frequency spectrum allocation.

Failure restoration of mobility databases for personal communication networks

Abstract: This paper studies failure restoration of mobility databases for personal communication networks (specifically, VLRs and HLRs). We model the VLR restoration with and without checkpointing. The optimal VLR checkpointing interval is derived to balance the checkpointing cost against the paging cost. We also model GSM periodic location updating (location confirmation) to quantify the relationship between the location confirmation frequency and the number of lost calls. The HLR failure restoration procedures for IS-41 and GSM are described. We show the number of lost calls in a HLR failure. Both the procedures in IS-41 and GSM cannot identify the VLRs that need to be accessed by the HLR after a failure. An algorithm is proposed to identify the VLRs, which can be used to aggressively restore a HLR after its failure.

Evaluation of location area planning scenarios in future mobile telecommunication systems

Abstract: In third generation mobile telecommunication systems, signalling requirements due to location updating and paging are expected to be remarkable, mainly because of the huge number of mobile subscribers. Location area planning is characterised by the trade-off between the number of location updates and the amount of paging signalling that the network has to deal with. Location area planning should be based on criteria which guarantee that signalling load will be kept under tolerable levels. Various approaches for location area planning in a city environment the worst case environment—are discussed in this paper. The simplest approach is the use of heuristic algorithms for approximating the optimum location area configuration. Then more complex scenarios which are based on geographical criteria (population distribution, highway topology, etc.) are investigated. Finally, user mobility characteristics are taken into account in the most complex scenarios. All scenarios are applied over a simulation model representing a city area, providing us with a very clear view of their performance characteristics.

Wireless data: systems, standards, service

Abstract: Wireless data products and services being proposed today include exotic mixes of services and technologies: packet transport over cellular circuits, facsimile service over Cellular Digital Packet Data (CDPD), voice and video over wireless LANs, and everything in between. Data networking terms that seem to have a clear meaning—data-link, network and transport layers; circuit-mode and datagram; connection-less and connection-oriented—in fact have meaning only in context. Thus TCP, a reliable packet transport protocol, is being used in CDMA circuit-mode data to provide a reliable data-link layer for the errorprone wireless link. IP datagrams will be transported over cellular links using dedicated channels with call establishment, possibly per packet. Market demands for timely solutions, competition between alternative technologies and the plethora of alternative fora for standards development are driving wireless data into fragmented directions. The primary constraints come from the limited spectrum, the need for security in the presence of mobility and the size and weight of mobile terminals and devices. Often the optimization for the latter constraints is sacrificed at the altar of the former drivers. Based upon our experience and work with standards and systems we attempt to put wireless data into perspective. We compare and contrast major services and products and identify the choices that were made and why.

Using direction and elapsed-time information to reduce the wireless cost of locating mobile units in cellular networks

Abstract: This paper proposes the use of easily-obtainable information to reduce the “wireless” cost of locating mobile units in cellular communication networks This comprises the direct cost of searching for them in different cells upon arrival of calls, as well as that of occasional position-updates issued by the units to reduce the number of cells that need to be searched The direction of motion at the time of last update is used to construct an asymmetric distance-based reporting boundary and, in conjunction with the elapsed time since the latest position-update, to optimize the search order For a Markovian motion model along a straight line and known motion parameters, optimal algorithms are provided The results suggest that substantial savings may be attained in common demanding situations such as commuter traffic in congested corridors

Integrating data traffic into a CDMA cellular voice system

Abstract: Part one of this paper analyzes the effects of data traffic integration into a CDMA cellular voice system. The figure of merit used for the quality of service seen by the voice users is measured by the probability of blocking. The CDMA system under consideration is a power controlled, cellular architecture in which blocking occurs when the total interference level exceeds the background noise level by 10 dB [1]. It is shown that the introduction of data can be done at little or no increase in the probability of blocking on the voice users. In part two we propose and analyze a protocol which achieves the efficient integration of data by maximizing the utilization of the resources and minimizing the delay experienced by the voice users. The proposed protocol admits data traffic into the CDMA cellular system based on the current aggregate voice interference level, and allows for the efficient integration of voice and data without degrading the quality of service for the delay-critical voice traffic.A Markovian model for this protocol is developed, evaluated and compared to computer simulation results.

Mobile wireless network system simulation

Abstract: This paper describes an advanced simulation environment which is used to examine, validate, and predict the performance of mobile wireless network systems. This simulation environment overcomes many of the limitations found with analytical models, experimentation, and other commercial network simulators available on the market today. We identify a set of components which make up mobile wireless systems and describe a set of flexible modules which can be used to model the various components and their integration. These models are developed using the Maisie simulation language. By modeling the various components and their integration, this simulation environment is able to accurately predict the performance bottlenecks of a multimedia wireless network system being developed at UCLA, determine the trade-off point between the various bottlenecks, and provide performance measurements and validation of algorithms which are not possible through experimentation and too complex for analysis.

Admission-control policies for multihop wireless networks

Abstract: In this paper, we investigate the admission-control problem for voice traffic in fixed-route circuit-switched wireless networks. We consider coordinate-convex admission-control policies and a “blocked-calls-cleared” mode of operation, in conjunction with the usual assumptions on the voice process statistics. These conditions result in a product-form stationary distribution for the voice state of the system, which facilitates the evaluation of network performance. However, to determine the optimal policy a large state space must be searched. We develop a recursive procedure to accelerate the evaluation of a large number of different admission-control policies, and a descent-search method to reduce significantly the number of policies that must be evaluated in searching for the optimal one. The numerical examples we present indicate that reduced blocking probability (or increased throughput) can be obtained by administering active admission control. The degree of improvement is highest in moderately overloaded traffic conditions, but it is typically small in low-capacity networks (at all loads). However, in applications where the performance measure associates different revenues or costs with the various call types, considerable improvement can be obtained when admission control is used.

Capacity and power control for CDMA microcells

Abstract: Capacity and power control issues are considered for urban CDMA microcells that operate on channels characterized by log-normal shadowing and Nakagami fading. The effects of fading on the desired and interfering signals, variations in the shadow standard deviation, imperfect power control, and the required E_b / N_o for satisfactory link operation are investigated. It is shown that the reverse channel is relatively insensitive, and the forward channel very sensitive, to shadow and fading variations. Power control error is shown to significantly degrade reverse channel capacity. Two biased forward channel power control strategies are introduced to enhance existing unbiased balancing forward channel power control algorithms.

Competitive multicast routing

Abstract: In this paper, we introduce and solve the multicast routing problem for virtual circuit environment without making any assumptions about the communication patterns, or about the network topology. By multicast we refer to the case were one source transmits to several destination the same information. Also, we allow arbitrary interleaving of subscription patterns for different multicast groups, i.e. the destinations for each group arrive at an arbitrary order and may be interleaved with destinations of other groups. Our goal is to make route selection so as to minimize congestion of the bottleneck link. This is the first analytical treatment for this problem in its full generality. The main contribution of this paper is an online competitive routing strategy that has an O(\log n \log ) d competitive factor where n is the size of the network and d \leq n is the maximum size of a multicast group.

On the performance of packet-switched cellular networks for wireless data communications

Abstract: 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'.

The design and implementation of a private message service for mobile computers

Abstract: Even as wireless networks create the potential for access to information from mobile platforms, they pose a problem for privacy. In order to retrieve messages, users must periodically poll the network. The information that the user must give to the network could potentially be used to track that user. However, the movements of the user can also be used to hide the user's location if the protocols for sending and retrieving messages are carefully designed. We have developed a replicated memory service which allows users to read from memory without revealing which memory locations they are reading. Unlike previous protocols, our protocol is efficient in its use of computation and bandwidth. In this paper, we will show how this protocol can be used in conjunction with existing privacy preserving protocols to allow a user of a mobile computer to maintain privacy despite active attacks.

Interworking between Digital European Cordless Telecommunications and a distributed packet switch

Abstract: The Digital European Cordless Telecommunications (DECT) standard specifies an air interface. DECT requires an external infrastructure to transfer information between wireless terminals, and to transfer information between a wireless terminal and a fixed network. The Public Switched Telephone Network, the GSM Cellular Network, Private Branch Exchanges and mobile data networks are all under investigation as DECT backbone networks. In this paper we look to the future and describe interworking between the DECT air interface and a wireless network infrastructure referred to as a Cellular Packet Switch. To achieve distributed network control, the Cellular Packet Switch uses an IEEE 802.6 Metropolitan Area Network to link base stations, databases and fixed networks. In this paper we specify details of DECT information transport on the Metropolitan Area Network. We also give examples of Network Layer message flows for location updating and handover. The messages for other key procedures including call origination and release appear in a more detailed technical report.

Performance evaluation of a reservation random access scheme for packetized wireless systems with call control and hand-off loading

Abstract: We consider a packet switched wireless network where each cell's communication channel is shared among packet voice sources. In this paper, we present a method for the design and analysis of wireless cells using a reservation random access (RRA) scheme for packet access control. This scheme is integrated with a call admission control procedure. We model the state process of a single cell as a vector Markov chain. We compute the steady state distribution of the Markov chain. This result is used to calculate the packet dropping probability and the call blocking probability. By setting limits on maximum permissible levels for the call blocking probability and the packet dropping probability, we obtain the Erlang capacity of a single cell, with and without hand-off traffic. For an illustrative RRA scheme, the Erlang capacity of a single cell is shown to be about twice that attained by a comparable fixed assigned TDMA scheme. We show that a cellular network using this RRA scheme and which applies can be no blocking of hand-off calls, exhibits similar call capacity levels.