Method for optimizing forward link coverage in code division multiple access (CDMA) network
First Claim
1. A method for optimizing forward link coverage in a code division multiple access (CDMA) network comprising the steps of:
- a) determining the morphology of a forward link coverage area;
b) determining azimuth orientation, tilt, gain and type of a base station antenna;
c) calculating power rating per channel for said coverage area;
d) determining RF output power per frequency assignment per sector for said coverage area;
e) simulating orthogonal channel noise which models noise generated by wireless communication traffic in an operational communication system of many subscribers;
f) establishing forward power control parameters;
g) performing a field-drive-test in which a mobile station receives test communication signals transmitted from said base station within specific regions of said coverage area, said mobile station measuring values for a received signal strength indicator (RSSI), a ratio (EC/IO) of pilot chip energy to total power spectral density, and a forward frame error rate (FFER);
h) comparing the measured RSSI value to a first threshold;
i) comparing said measured ratio (EC/IO) to a second threshold;
j) comparing said measured FFER to a third threshold;
k) determining if chip delay measured at the mobile station exceeds a fourth threshold, and if so, making adjustments to base station equipment to attempt to reduce said chip delay;
l) determining whether a shade area exists by comparing said RSSI, EC/IO, FFER with a basis of overall network design;
m) determining whether transmit/receive links are balanced; and
n) designating forward link coverage as being satisfied when comparisons to said first, second and third thresholds are favorable and the transmit/receive links are balanced;
otherwise, making adjustments to base station equipment to attempt to correct unfavorable comparisons to said thresholds and to correct an imbalance between the transmit/receive links.
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Abstract
Disclosed is a method for optimizing forward link coverage in a spread spectrum communication system, e.g., CDMA system. Spread spectrum test communication signals are transmitted from a base station at a known power level, using an antenna having a known beam direction. Orthogonal channel noise is simulated in order to model noise generated by wireless communication traffic existing in an operational communication system of many subscribers. A mobile station receives the test communication signals in a specific region of a cell, and measures signal quality parameters, e.g., RSSI, Ec/Io and a forward frame error rate (FFER), from the received signals and simulated noise. The measured signal quality parameters are compared to respective criteria. Each region is designating as being satisfactorily covered by the base station if the measured signal quality parameters substantially satisfy the criteria. Otherwise, base station equipment is adjusted to modify the transmission of the test communication signals, and the process is repeated.
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Citations
17 Claims
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1. A method for optimizing forward link coverage in a code division multiple access (CDMA) network comprising the steps of:
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a) determining the morphology of a forward link coverage area;
b) determining azimuth orientation, tilt, gain and type of a base station antenna;
c) calculating power rating per channel for said coverage area;
d) determining RF output power per frequency assignment per sector for said coverage area;
e) simulating orthogonal channel noise which models noise generated by wireless communication traffic in an operational communication system of many subscribers;
f) establishing forward power control parameters;
g) performing a field-drive-test in which a mobile station receives test communication signals transmitted from said base station within specific regions of said coverage area, said mobile station measuring values for a received signal strength indicator (RSSI), a ratio (EC/IO) of pilot chip energy to total power spectral density, and a forward frame error rate (FFER);
h) comparing the measured RSSI value to a first threshold;
i) comparing said measured ratio (EC/IO) to a second threshold;
j) comparing said measured FFER to a third threshold;
k) determining if chip delay measured at the mobile station exceeds a fourth threshold, and if so, making adjustments to base station equipment to attempt to reduce said chip delay;
l) determining whether a shade area exists by comparing said RSSI, EC/IO, FFER with a basis of overall network design;
m) determining whether transmit/receive links are balanced; and
n) designating forward link coverage as being satisfied when comparisons to said first, second and third thresholds are favorable and the transmit/receive links are balanced;
otherwise, making adjustments to base station equipment to attempt to correct unfavorable comparisons to said thresholds and to correct an imbalance between the transmit/receive links.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification