We analyze the uplink outage probability at the randomly, but not necessarily independently nor homogeneously, distributed cellular network receivers caused by an overlaid secondary ad hoc network. Unlike the previous works that assumed exact circular exclusion regions (or guard zones), we incorporate a sensing mechanism to decrease the significant effect of the nearby interferers. We consider Rayleigh-faded links, large-scale power control, and the knowledge of the initial outages in the absence of the secondary network. We derive an upper bound on the outage probability and show it to be tight when the co-channel primary receivers are separated by relatively significant distances, which is inherently the case for the cellular network. Furthermore, we derive a closed-form expression that shows the significant impact of the sensing mechanism on the spectrum sharing gains.. Additionally, we optimize the decision threshold, which is used by secondary network users to decide whether to transmit or not, in order to maximize the spectrum sharing gains under the given outage constraints.

A closed-form expression for the outage probability at a receiver in the primary network due to a uniform annular sector distribution of secondary transmitters is derived in a Rayleigh fading environment. This may include an exclusion region, and a finite or infinite outer radius. Conversely, under a given constraint on the outage probability, spectrum sharing opportunities are analyzed with respect to the field size and are shown to be significantly dependent on the exclusion region. Conditions are obtained for which an infinite field size assumption can or cannot lead to the loss of spectrum sharing opportunity. Additionally, the spectrum sharing gains (the maximum average number of secondary transmitters) are derived for the secondary network for different spatial deployments. It is worth mentioning that other than networks sharing spectrum, the derived results are applicable to any set of interferers from the same network or other networks around any receiver of study.

Enabling unsubscribed Secondary User (SU) access through Dynamic Spectrum Access (DSA) techniques provides a huge opportunity to the Wireless Service Providers (WSPs) for achieving efficient radio spectrum usage as well as gain additional profits. This paper presents a novel and dynamic SU pricing model for implementation by the WSPs at their Base Stations (BSs) based upon a BS-centric distributed framework, that allows the SU price to vary dynamically with the changing radio spectrum usage at the BS. Assuming high competition among regional WSPs, a non-cooperative competition structure is considered among the WSPs, where neither information nor resources are shared among the WSPs. A simple single cell scenario easily scalable to multiple cells achieving competitive yet dynamic SU pricing among the BSs of two WSPs, is presented in this paper. The final SU price is seen to depend on the spectrum utilization at the BS, the wireless channel, and the price charged by WSPs to their PUs.

We investigate the use of distributed measurements for estimating and updating the performance of a cellular system. Specifically, we discuss the number and placement of sensors in a given cell for estimating its signal coverage. Here, an "outage" is said to occur at a location if a mobile receiver there has inadequate signal-to-noise ratio (SNR -based outage) or, using another criterion, inadequate signal-to-interference ratio (SIR- based outage); and the "outage probability" is the fraction of the cell area over which outage occurs. A design goal is to improve measurement efficiency (i.e., minimizing the required number of measurement sensors) while accurately estimating the outage probability and mapping the coverage holes. The investigation uses a generic path loss model incorporating distance effects and spatially correlated shadow fading. Our emphasis is on the performance prediction accuracy of the sensor network, rather than on cellular system analysis per se. Through analysis and simulation, we assess several approaches to estimating the outage probability. Applying the principle of importance sampling to the sensor placement, we show that a cell outage probability of Pocan be accurately estimated using ~ 10/Popower-measuring sensors distributed in a random uniform way over the area with base-sensor distances from 50% to 100% of the cell radius. This result applies to both SNR-based and SIR-based outage estimation for both indoor and outdoor environments.

Fixed relays are expected to be a part of future infrastructure-based wireless networks. Besides coverage extension, such relays can form advanced architectures due to the flexibility in their power expenditure and physical size. This paper explores the potential benefits of multi-antenna relays for spatial multiplexing of independent data sources sending data to a common multi-antenna destination such as a base station or an access point. Overall, the system resembles a horizontally coded layered space-time architecture. In particular, we consider zero forcing decision feedback (ZF-DF) type MIMO receivers and study their outage performance under various (non-selective and selective) digital relaying protocols. For diversity relaying protocol, we propose two schemes, Joint ZF-DF and Parallel ZF-DF, for joint processing (combining and decoding) of the direct user signals and the signal from the relay. We show that with the proposed selective diversity relaying protocols and joint ZF-DF processing, the outage probability of the system can be decreased significantly.

We investigate the use of an auxiliary network of sensors to assist radio resource management in a cellular system. Specifically, we discuss the number and placement of sensors in a given cell for estimating its signal coverage. Here, an "outage" is said to occur at a location if the mobile receiver there has inadequate signal-to-noise ratio (SNR-based outage) or, using another criterion, inadequate signal-to-interference ratio (SIR-based outage); and the "outage probability" is the fraction of the cell area over which outage occurs. A design goal is to confine the number of sensors per cell to an acceptable level while accurately estimating the outage probability. The investigation uses a generic path loss model incorporating distance effects and spatially correlated shadow fading. Our emphasis is the performance prediction accuracy of the sensor network, rather than cellular system analysis per se. Through analysis and simulation, we assess several approaches to estimating the outage probability. Applying the principle of importance sampling to the sensor placement, we show that a cell outage probability of ~ Po can be accurately estimated using ~ 10/Po power-measuring sensors distributed in a random uniform way over base-mobile distances from 50% to 100% of the cell radius. This result applies to both SNR-based and SIR-based cases, in both indoor and outdoor environments.

The concept of relaying is a promising solution for the challenging throughput and high data rate coverage requirements of future wireless cellular networks. In this paper, we demonstrate that the area that a single BS (base station) can provide high data rate coverage can significantly be increased by the employment of digital fixed relays without any penalty in capacity. This network architecture, which allows two-hop links, is expected to facilitate cost-efficient high data rate coverage in beyond-3G cellular wireless networks. In particular, we considered the downlink of a non-CDMA network where 6 digital fixed relays are placed around each BS in a hexagonal layout. The improved two-hop links can be exploited to yield higher throughput through the use of adaptive modulation and coding.

Abstract Wireless networks are evolving to include Internet access to interactive multimedia and video conferencing as well as traditional services such as voice, email and web access. These new applications can demand large amounts of network resources, such as bandwidth, to achieve the highest levels of quality (e.g. picture quality). In conjunction with this trend, charging and resource allocation systems must evolve to explicitly consider the trade‐off between resource consumption and the Quality of Service (QoS) provided. This paper proposes a novel QoS‐based charging and resource allocation framework. The framework allocates resources to customers based on their QoS perceptions and requirements, thereby charging fairly while improving resource allocation efficiency. It also allows the network operators to pursue a wide variety of policy options, including maximizing revenue or using auction or utility‐based pricing. Copyright © 2003 John Wiley & Sons, Ltd.

Abstract Future wireless evolution envisages high rates, low hierarchy in the network architecture, antenna array processing, multiple access modes and multihop operation as part of the system concept. To exploit the increased capabilities of the systems in conception, efficient resource management strategies need to be developed. The goal of this paper is to examine the key aspects of the evolution which impact radio resource management for the mobile broadband wireless network, and to emphasize the areas that need to be addressed for servicing mobile users with varying quality of service requirements. Copyright © 2003 John Wiley & Sons, Ltd.

It is shown that the classical additive white Gaussian noise (AWGN) channel design can be retained for the fading channel with any degree of fading, if carried out with the appropriate signal set size M=M/sub min/. The size of the signal set M/sub min/ is shown to depend upon the number of parallel transitions between a given pair of states and the throughput rate. In the proposed multiple trellis-coded modulation (MTCM) scheme with a modified design (MTCM (MD)), the output bits from a rate m/m+1 trellis encoder are assigned multiple signals from an M/sub min/-PSK signal set. Compared to the MTCM with set partitioning proposed for the fading channel (SPF) design, the MTCM (MD) scheme provides the same signal diversity and the same or increased values of the branch distance product, and always leads to increased value of d/sup 2/(free). As a result, the performance is always improved on the Rician fading channel due to the increased d/sup 2/(free), and is improved on any fading channel when an increase in branch distance produce P takes place. When compared to the MTCM with the set partitioning optimum for the AWGN channel (SPA) design, the MTCM (MD) scheme, under certain conditions, provides the same value of d/sup 2/(free) as the MTCM (SPA) design, and is then asymptotically optimum for both the AWGN channel and the fading channels.>

The authors explore the trellis coding of continuous-phase quadrature frequency/phase modulated (CPQFPM) signal sets and continuous-phase FPM (CPFPM) signal sets, which are embodiments of the quadrature biorthogonal modulation (QBOM) technique. Conventional TCM and multiple TCM schemes with these modulation formats are examined using both the AWGN channel and the Rician fading channel design. Asymptotic coding gains in d/sup 2/(free) are tabulated for trellis-coded rate 3/4, 5/6, and 6/7 QFPM schemes, in comparison with uncoded modulations (8AMPM, 32AMPM) and other trellis-coded modulations (TCM (2FSK/4PSK 16QAM, 64QAM), MTCM (2FSK/8PSK)) of equivalent throughput rate. Performance gains on the Rician fading channel are demonstrated by increased values of the design parameters for this channel, namely symbol diversity L/sub min/ and branch distance product P.>

Multiple trellis coded modulation of constant envelope frequency and phase modulated signal sets (MTCM/FPM) is investigated for performance on the additive white Gaussian noise (AWGN) channel and on the one-sided normal, Rayleigh and Rician fading channels. The Nakagami-m fading model is used as an alternative to the Rician fading model to calculate the error probability upper bound for trellis-coded schemes on the fading channel. The likeliness and the disparity between the upper bounds to the error probability for the two fading models are discussed. The design criteria for the one-sided normal fading channel, modeled by the Nakagami-m distribution, are observed to be the same as those for the Rayleigh-fading channel. For the MTCM/FPM schemes, it is demonstrated that the set partitioning designed to maximize symbol diversity (optimum for fading channels) is optimum for performance on the AWGN channel as well. The MTCM/FPM schemes demonstrate improved performance over MTCM/MPSK schemes and TCM/FPM schemes on the AWGN channel and the fading channel.>