Dual channel dual speed FM subcarrier paging system
First Claim
1. A wireless paging system that transmits digital messages on an FM baseband, comprising:
- a transmitter circuit having at least one of a first and a second transmission data rate, the second transmission data rate being slower than the first data rate; and
a pager receiver that receives messages at both the first and second transmission data rate and selectively decodes the messages at one of said first transmission data rate and said second transmission data rate according to a given transmission coverage in a geographical region,wherein the transmitter circuit includes a first transmitter channel for transmitting a first subcarrier containing the message at one of said first and second transmission data rates and a second transmission channel for generating a second subcarrier containing the message at one of said first and second transmission data rates.
4 Assignments
0 Petitions
Accused Products
Abstract
The effective transmission range of a wireless paging system is varied by changing the transmission data rate. The transmission data rate is lowered in regions with sparse transmitter coverage to increase the effective transmission range of the transmitter. The dual transmission data rates are transmitted either on separate subcarriers on the same FM channel, on the same subcarrier of different FM channels or alternatively on different subcarriers of different FM channels. In a region with dense transmission coverage, the receiver decodes transmission messages at the faster transmission data rate. In regions with sparce transmission coverage, the receiver decodes messages at the slower transmission data rate.
33 Citations
12 Claims
-
1. A wireless paging system that transmits digital messages on an FM baseband, comprising:
-
a transmitter circuit having at least one of a first and a second transmission data rate, the second transmission data rate being slower than the first data rate; and a pager receiver that receives messages at both the first and second transmission data rate and selectively decodes the messages at one of said first transmission data rate and said second transmission data rate according to a given transmission coverage in a geographical region, wherein the transmitter circuit includes a first transmitter channel for transmitting a first subcarrier containing the message at one of said first and second transmission data rates and a second transmission channel for generating a second subcarrier containing the message at one of said first and second transmission data rates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method for varying an effective transmission range for transmitters in a wireless communication system, comprising:
-
transmitting messages at a first transmission data rate; transmitting the same messages at a second transmission data rate slower than the first transmission data rate; receiving messages at both the first and second transmission data rate; decoding messages at one of said first transmission data rate and said second transmission data rate to selectively vary the effective range over which the messages can be received from the transmitter, and including transmitting messages at the first transmission data rate on a first subcarrier on a given broadcast channel and transmitting messages at the second transmission data rate on a second subcarrier on the same broadcast channel. - View Dependent Claims (11)
-
-
12. A wireless communication system with variable transmission range, comprising
multiple transmitters having at least one of a first and second transmission bit rate; - and
a receiver including means for selectively decoding messages from the multiple transmitters at both the first transmission bit rate and the second transmission bit rate according to transmission coverage in a given region, wherein the receiver comprises the following; a first filter for extracting messages at a first subcarrier frequency; a second filter for extracting messages at a second subcarrier frequency; a first demodulator coupled to the first filter; and a second demodulator coupled to the second filter, the first and second demodulators selectively demodulating the first and second subcarrier at one of said first and said second transmission bit rate.
- and
Specification