Showing papers on "Co-channel interference published in 1985"

Cochannel interference measurement in mobile radio systems

Abstract: A new cochannel interference measurement method for mobile communications, which uses the beat phenomena in the resultant envelope of signal and interference, is proposed. This method has been proven both theoretically and experimentally able to measure CIR up to 15 dB within a fading frequency of 80 Hz. The interference measurement circuit using a widely available 1-chip microprocessor is designed. The program and data memories is about 2k byte. Further, an interference reduction effect by intra-zone channel reassignment, in the case of increasing interference, is clarified by computer simulation. Intra-zone channel reassignment is achieved by using both the cochannel interference measurement and channel exchange techniques.

Adaptive slow frequency-hopping system for land mobile radio

Abstract: The essential features of a novel adaptive slow frequency-hopping system are described. It is proposed that the system would operate in the heavily congested VHF private mobile radio bands by selecting currently inactive channels, hence increasing the overall spectral efficiency. A preliminary analysis of mutual interference is presented in full, the results of which indicate that a frequency-hopping system with a viable capacity could coexist with conventional private mobile radio networks.

Relationship between base station transmitter multicoupling requirements and frequency planning strategies for cellular mobile radio

Abstract: Frequency assignment procedures in mobile radio systems generally aim at achieving a measure of intermodulation compatibility, and, in principle, provided sufficient numbers of channels are available and may be assigned with the minimum of restrictions, then this objective is achievable (at least as far as third-order products are concerned). However, in cellular systems, additional constraints are imposed by the need to multicouple cell centre base station transmitters on to a common an tenna, and this requirement sets a lower limit on the minimum frequency separation at cell centres, which, in turn, makes achievement of third-order compatible frequency plans extremely difficult. The paper examines the relationship between the minimum frequency separation for third-order compatibility and the number of available channels and cell cluster size, in order to identify optimum configurations.

Cochannel interfermce measurement in mobile radio systes

Abstract: A new cochannel interference measurement method for mobile communications, which uses the beat phenomena in the resultant envelope of signal and interference, is proposed. This method has been proven both theoretically and experimentally able to measure CIR up to 15 dB within a fading frequency of 80 Hz. The interference measurement circuit using a widely available I-chip microprocessor is designed. The program and data memories is 2k byte. Further, an interference reduction effect by intra-zone channel reassignment, in the case of increasing interference, is clarified by computer simulation. Intra-zone channel reassignment is achieved by using both the cochannel interference measurement and channel exchange techniques.

A Practical Culling Strategy to Assist Frequency Assignment for Land Mobile Radio Systems

Abstract: This pape r d e s c r i b e s a p r a c t i c a l c u l l i n g s t r a t e g y to a s s i s t f r e q u e n c y a s s i g n m e n t s for Land M o b i l e ra d i o s y s t e m s in the t w o s i g n a l third-order receiver i n t e r m o d u 1 at i o n i n t e r f e r ­ ence analysis. This strategy is used to identify the potential conflict s i t u a t i o n s w h i c h have a r e l a t i v e l y hig he r p r o b a b i l i t y of interference so that the number of calculations that have to be performed in an interference analysis may be m i n i m i z e d . The r e s u l t s of the a n a l y s i s are presented on a graph depicting the relationship between the two culling limits of distance and fre qu enc y separation.