Method for optimizing spectral re-use
AssigneeNortel Networks Limited
InventorsMini Vasudevan, Sheng-Chou Lin, Stone H. Tseng
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Abstract
A method for optimizing spectral re-use between an interferer digital phase modulated cellular system and a desirable analog phase modulated cellular system is disclosed wherein an optimal guard band to use with adjacent channel interference is determined, or an optimal guard zone to use with co-channel interference is determined. This is achieved by determining the effect of interference due to a digital phase modulated signal at the baseband of a desired analog phase modulated signal. By the use of this invention, the capacity of a desired system and/or the quality of a service provided by a desired system may be enhanced.
Claims12
A method for optimizing spectral re-use between an interferer digital phase modulated cellular system utilizing a first transmitter/receiver configurable to operate substantially at a first frequency, and a desirable analog phase modulated cellular system utilizing a second transmitter/receiver configurable to operate substantially at a second frequency, the first and second transmitter/receivers being separated by a re-use distance, the method comprising the steps of:
- determining a carrier-to-interference ratio (CIR) with reference to the re-use distance;
- setting an acceptable baseband signal-to-interference ratio (SIR);
- determining an interference reduction factor (IRF) as the ratio of the SIR to the CIR;
- determining an optimum frequency separation f.sub.d with reference to the power spectral density of the random phase angle, an interference-to-signal-carrier power ratio, and autocorrelation functions of the baseband phase modulated processes;
- configuring the first transmitter to operate substantially at the first frequency;
- and
- configuring the second transmitter to operate substantially at the second frequency, wherein the second frequency is substantially separated in bandwidth from the first frequency by at least the determined frequency separation f.sub.d.
A method for optimizing spectral re-use between an interferer digital phase modulated cellular system utilizing a first base station antenna operative substantially at a first frequency, and a desirable analog phase modulated cellular system utilizing a second base station antenna operative substantially at a second frequency, the first frequency and second frequency being substantially separated in bandwidth by a frequency separation of f.sub.d, the method comprising the steps of:
- determining the power spectral density of the random phase angle at the separation frequency f.sub.d, with reference to the interference-to-signal carrier power ratio, the separation frequency f.sub.d, and autocorrelation functions of the baseband phase modulated processes;
- determining an interference reduction factor (IRF) with reference to the baseband power spectral density of the desired signal, the power spectral density of a random phase angle at f.sub.d, and an interference carrier-to-signal carrier power ratio;
- setting an acceptable baseband signal-to-interference ratio (SIR);
- determining a carrier-to-interference ratio (CIR) as a ratio of the SIR to the IRF;
- determining the re-use distance with reference to the CIR;
- and
- spacing apart the first base station antenna and the second base station antenna to obtain at least the determined re-use distance therebetween.
Dependencies are inferred from the claim text.