The problem of meeting the proliferating demands for mobile telephony within the confinement of the limited radio spectrum allocated to these services is addressed. A multiple-beam adaptive base-station antenna is proposed as a major system component in an attempt to solve this problem. The approach is demonstrated by employing an antenna array capable of resolving the angular distribution of the mobile users as seen at the base-station site, and then using this information to direct beams toward either lone mobiles, or groupings of mobiles, for both transmit and receive modes of operation. The energy associated with each mobile is thus confined within the addressed volume, greatly reducing the amount of cochannel interference experienced from and by neighboring cochannel cells. To ascertain the benefits of such an antenna, the conventional and proposed antenna systems are modeled in a typical mobile radio environment. For a given performance criterion, the theoretical results indicate that a significant increase in the spectral efficiency, or capacity, of the network is obtainable with the proposed antenna. >

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The performance enhancement of multibeam adaptive base-station antennas for cellular land mobile radio systems

Reuse distance aid cluster size are evaluated for cellular mobile radio systems. Rayleigh fading, log-normal shadowing, and area mean power (which is inversely proportional to the fourth power of propagation distance) are considered, using the technique of Schwartz and Yeh (1982) for determining the probability density function of the sum of several log-normal variables in order to obtain the cochannel interference probabilities. These results are used for analyzing the radio spectrum efficiency, taking traffic intensity into consideration. Different modulation methods, namely, analog FM with 30 kHz and 12.5 kHz channel spacing, SSB (single sideband) with 5 kHz spacing, and digital modulation with 25 kHz channel spacing, with adequate protection ratios are compared. An example of the calculation of system bandwidth and cluster size using this procedure is presented. >

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Improved assessment of interference limits in cellular radio performance

A novel mathematical method is presented to express the outage probability for a desired radio signal received from a mobile transmitter in the presence of multiple interfering signals with combined log-normal and Rayleigh fading. In contrast to previously reported analyses, this exact method avoids approximation of the PDF of the received powers of the various signals. This is useful in determining the spectrum efficiency and performance of (interference-limited) radio networks for high-capacity cellular telephony, two-way paging, packet radio and other mobile data networks. >

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Exact analysis of the outage probability in multiple-user mobile radio

Spectrum efficiencies for single-cell trunked and cellular mobile radio systems are analyzed, taking into consideration fading circumstances and call blocking probability. Two kinds of transmit power control methods are considered. One retains area mean power at the receiver constant and the other retains local mean power constant. For single-cell trunked systems, it has been shown how spectrum efficiency is limited by the required traffic quality or permitable adjacent channel interference. A narrower channel spaced system shows superiority to wide-band systems, if an adjacent channel interference protection ratio is lower than about -40 dB and a few percent interference probability is permitted. On comparing cellular systems, superiority in spectrum efficiency is determined by the product of protection ratio and channel spacing. Call blocking probability and interference have little effect on spectrum efficiency comparison. For both systems, the two kinds of transmit power control and the two interchannel interference criteria show no significant difference between their effects on spectrum efficiency.

Analysis for spectrum efficiency in single cell trunked and cellular mobile radio

The authors address the problem of meeting the proliferating demands for mobile telephony within the confinements of the limited radio spectrum allocated to these services. A multiple-beam adaptive base-station antenna is proposed as a major system component in an attempt to solve this problem. The approach is demonstrated by employing an antenna array to resolve the angular distribution of the mobile users as seen at the base-station site, and then using this information to direct beams towards the mobiles in both transmit and receive modes. The energy associated with each mobile is thus confined within the addressed volume, greatly reducing the number of co-channel cells. For a given performance criterion, this results in an increase in the spectral efficiency or capacity of the network. The concept is demonstrated using results generated by a computer simulation of a simplified mobile scenario. The realization of a fully adaptive base-station antenna test rig is discussed. >

/pdf/multi-beam-adaptive-base-station-antennas-for-cellular-land-3kyy3kypp3.pdf

Multi-beam adaptive base-station antennas for cellular land mobile radio systems

Origination probability for cochannel interference is introduced to the study of the influence of all cochannel interferers surrounding the base station of interest. In addition, the probability of cochannel interference, which is of importance in determining system parameters in a cellular communication scheme, is evaluated for the mobile radio environment as expressed by Rayleigh fading and shadowing. As a consequence, the optimal number of radio channels to allocate to each cell is derived through the use of a simple mathematical model. The theoretical results obtained are useful not only as a step in the maturation of the cellular land mobile radio system, but also for the development of the portable radio telephone system.

H. Ohdate

Papers

Optimal channel reuse in cellular land mobile radio systems