Cell selection techniques for frequency division multiple access systems

Abstract

This disclosure is directed to power estimation techniques for use by a subscriber unit of a frequency division multiple access (FDMA) system during the cell selection process. The power estimation techniques recognize that adjacent cells, i.e., adjacent in terms of frequency, often have slight overlap. Thus, the power from a signal associated with one cell can cause power to be detected in an adjacent cell, even if no signal is actually present in the adjacent cell. In accordance with this disclosure, techniques are described for identifying, reducing or eliminating the detection of false positives in such adjacent cells. By identifying, reducing or eliminating the detection of false positives, the cell selection process can be accelerated and additional processing of false positive signals in such adjacent cells can be avoided.

1 . A method comprising: 
 receiving a signal associated with a cell of a frequency division multiple access (FDMA) system, the cell spanning a first frequency range;    filtering the signal to a second frequency range, wherein the second frequency range is smaller than the first frequency range; and    measuring power of the filtered signal to identify an estimate of power associated with the cell.    
   
   
       2 . The method of  claim 1 , wherein the FDMA system comprises a global system for mobile communications (GSM) system.  
   
   
       3 . The method of  claim 2 , wherein the first frequency range is approximately 200 kilohertz and the second frequency range is approximately 100 kilohertz.  
   
   
       4 . The method of  claim 1 , further comprising: 
 filtering a plurality of signals associated with cells of the FDMA system to the second frequency range;    measuring power of the plurality of filtered signals;    prioritizing the plurality of filtered signals based on the measured power of the filtered signals;    selecting a desirable one of the cells based at least in part on the prioritization; and    registering with a network associated with the desirable cell.    
   
   
       5 . A subscriber unit of a frequency division multiple access (FDMA) system comprising: 
 a receiver to receive a signal associated with a cell of a frequency division multiple access (FDMA) system, the cell spanning a first frequency range; and    a control unit to filter the signal to a second frequency range, wherein the second frequency range is smaller than the first frequency range, and measure power of the filtered signal to identify an estimate of power associated with the cell.    
   
   
       6 . The subscriber unit of  claim 5 , wherein the FDMA system comprises a global system for mobile communications (GSM) system.  
   
   
       7 . The subscriber unit of  claim 6 , wherein the first frequency range is approximately 200 kilohertz and the second frequency range is approximately 100 kilohertz.  
   
   
       8 . The subscriber unit of  claim 5 , wherein the control unit filters a plurality of signals associated with cells of the FDMA system to the second frequency range, measures power of the plurality of filtered signals, prioritizes the plurality of filtered signals based on the measured power of the filtered signals, selects a desirable one of the cells based at least in part on the prioritization, and causes the subscriber unit to register with a network associated in the desirable one of the cells.  
   
   
       9 . A computer-readable medium comprising instructions to cause subscriber unit of a frequency division multiple access (FDMA) system to: 
 receive a signal associated with a cell of the FDMA system, the cell spanning a first frequency range;    filter the signal to a second frequency range, wherein the second frequency range is smaller than the first frequency range; and    measure power of the filtered signal to identify an estimate of power associated with the cell.    
   
   
       10 . The computer-readable medium of  claim 9 , wherein the FDMA system comprises a global system for mobile communications (GSM) system.  
   
   
       11 . The computer-readable medium of  claim 10 , wherein the first frequency range is approximately 200 kilohertz and the second frequency range is approximately 100 kilohertz.  
   
   
       12 . A subscriber unit of a frequency division multiple access (FDMA) system comprising: 
 means for receiving a signal associated with a cell of the FDMA system, the cell spanning a first frequency range;    means for filtering the signal to a second frequency range, wherein the second frequency range is smaller than the first frequency range; and    means for measuring power of the filtered signal to identify an estimate of power associated with the cell.    
   
   
       13 . The subscriber unit of  claim 12 , wherein the FDMA system comprises a global system for mobile communications (GSM) system, and the first frequency range is approximately 200 kilohertz and the second frequency range is approximately 100 kilohertz.