The Personal Access Communications System (PACS) is an air interface standardized by the American National Standards Institute (ANSI). It is a low tier wireless communications system designed to support high quality voice, voiceband data, digital data, and messaging services. This paper describes third generation advancements to PACS. Our proposed protocol, GPRS-PACS, adopts principles of GPRS over the PACS physical layer to handle packet traffic. The issues covered include protocol layering, the channel and superframe structures, the RLC/MAC block formats, and the MAC layer procedures.

The FCC has allocated two 10 MHz bands of spectrum (1910-1920 MHz and 2390-2400 MHz) for asynchronous unlicensed operation under a specific set of physical layer and media access layer constraints known as the asynchronous etiquette. Little information is available on the details of the performance of the etiquette. This paper provides a first-cut evaluation of the theoretical limits on the throughput and delay performance of the etiquette. The work studies, via simulation, the effects of propagation delays and hardware latencies. The simulation is calibrated by considering specific subcases for which simple analytic results are easily found. Numerical results illustrate the performance.

Handover is the process by which a mobile terminal maintains a communication session as it crosses through the coverage area of the grid of base stations providing service in a cellular wireless system. Because of imperfect channel measurements, it is difficult to determine the correct point for a handover. Acting too soon may force a handover back to the original base station; delaying too long may make it impossible for the mobile to meet its quality of service objectives. It is important to quantify the handover delay in terms of various system parameters in order to efficiently design cellular wireless communication systems. This paper presents an exact expression for handover delay as a function of the base station separation, the standard deviation of log-normal shadowing, and the averaging distance. It also presents a simple closed form approximation that includes the hysteresis margin. These are the first such expressions available within the literature. The approximation is validated via simulation and is shown to work well over the range of interest.

There is a growing interest in the research community in mechanisms that transport asynchronous transfer mode (ATM) cells over a wireless link (wireless-ATM), and in wireless access to ATM backbone networks (broadband wireless networking). This paper presents an architecture for broadband wireless networking that supports PCS (personal communication services) using an ATM backbone. We develop analytical and simulation models to measure the delay of PCS registration and call delivery. The performance models are illustrated with numerical examples that reveal the high sensitivity to the processing speed of network entities. Their agreement provides a first cut engineering approximation that can easily be applied to other networks and systems.

Future microcellular personal communications systems (PCSs) will be characterized by high user density and high mobility. It is expected that registrations will incur a large amount of the radio link signaling traffic. A profile-based strategy (PBS) is proposed to reduce the signaling traffic on the radio link by increasing the intelligence within the fixed network. The system maintains a sequential list of the most likely places where each user is located. The list is ranked from the most to the least likely place where a user is found. When a call arrives for a mobile, it is paged sequentially in each location within the list. When a user moves between location areas in this list, no location update is required. The list may be provided by the user or may be based on each user's past calling history. The method for doing this is outside the scope of this work. This work focuses on the potential performance improvements that can result from maintaining such a list. This paper compares the performance of the proposed strategy to the typical geographic-based location-tracking schemes being implemented in evolving digital cellular and cordless standards. Key performance measures for the comparison are radio bandwidth, fixed network SS7 traffic, and call setup delay. We investigate the conditions under which the PBS performs better than the traditional scheme. Results indicate that over a wide range of parameters, it may be possible to reduce both the radio bandwidth and fixed network signaling load for a modest increase in call setup delay.

The increased demand for wireless mobile communications coupled with the finite available spectrum has motivated investigation into alternative methods of tracking users and delivering calls. We present a new scheme for delivering mobile terminated calls named reverse virtual call setup (RVC). Only a few new fixed network SS7 signaling messages are needed to implement this protocol; we specify them here. RVC can function within the existing cellular paging network or with an integrated overlaid paging network. The relative performance of RVC for both scenarios is investigated.

Future microcellular personal communications systems (PCS) will be characterized by high user density and high mobility. It is expected that registrations will incur a large amount of the radio link signaling traffic. A profile-based strategy (PBS) is proposed to reduce the signaling traffic on the radio link by increasing the intelligence within the fixed network. The fixed network performance of the PBS was investigated previously. This paper compares its radio bandwidth and call setup delay performance to the typical geographic based location tracking schemes in evolving digital cellular and cordless standards. We investigate the conditions under which the PBS performs better than the traditional scheme. Results of this work together with the previous work indicate that over a wide range of parameters it may be possible to reduce both the radio bandwidth and fixed network signaling load for a modest increase in call setup delay.

At the switch boundaries of cellular systems, it is necessary to provide an inter-switch handover procedure if calls are to remain in progress as users cross these boundaries. Both the North American and Pan European second generation standards provide mechanisms for inter-switch handover. Motivated by the need to develop procedures for inter-switch handover in the cellular packet switch (CPS), this paper develops a general set of procedures for inter-switch handover that, unlike their second generation counterparts, provide a mechanism for the transport of data. Unlike voice, data packets must all be delivered. The delivery may need to be sequential and/or restricted to a single copy. The path optimization procedures are all presented in the context of the CPS. In addition, we identify capabilities needed by the CPS and present suitable protocols. The path optimization procedures are evaluated based on the following performance criteria: guarantee of sequential delivery, avoidance of multiple copies, and delay. Fundamental limitations on data throughput result if both sequential delivery and a single copy are required.

Future high density wireless communication systems will place large demands upon the signaling channel between the mobile terminals and the fixed network infrastructure. One such signaling channel protocol is resource auction multiple access (RAMA). This paper evaluates the performance of a low complexity extension to RAMA called tree-search RAMA (TRAMA). TRAMA employs a close variant of a classic tree search mechanism to more effectively utilize a given bandwidth. We derive bounds on the delay-throughput characteristics of TRAMA. Under heavy traffic conditions where RAMA is unusable TRAMA is able to operate with finite average delay. For light to moderate traffic the average delay performance is only slightly better for TRAMA. However TRAMA operates with a lower variance of delay. Furthermore, the variance decreases when the average offered traffic increases. We show that this implies that TRAMA is less sensitive to the spatial and temporal variability of a mobile wireless environment.>

Future wireless information networks will employ dense grids of base stations to support a high user population. While small cells mitigate capacity problems, lengthen battery life, and improve signal quality, the frequent movement of users across cell boundaries imposes new burdens on network controllers. Previous work suggests that a cellular packet switch, based on distributed network control, can support high density personal communications. This paper proposes an allocation of control functions to elements of the cellular packet switch and specifies the flow of information within the switch. Message flows, defined for key procedures, form the foundation of a network layer protocol. Functionality is divided into the categories of call processing (set up and release), mobility management (location updates, handover, and path optimization), and radio resource management. Central office switches perform call processing. Mobility management and radio resource management are performed by interface units of the metropolitan area network at the heart of the cellular packet switch. This architecture delivers advanced services with minimal impact on central office switch software. It also relies on distributed, rather than centralized mobility management to provide prompt, accurate communications as users move about.>