Method and apparatus for overlaying two CDMA systems on the same frequency bandwidth
First Claim
1. A method of overlaying a second CDMA system over a first CDMA system comprising the steps of:
- transmitting a first signal as a first transmitted signal using a first CDMA channelization;
transmitting a second signal as a second transmitted signal using a second CDMA channelization, wherein said first and second CDMA channelization share at least a portion of a common frequency spectrum and wherein said first transmitted signal and said second transmitted signal are transmitted as a combined output into a common coverage area;
obtaining signal energy from said combined output corresponding to said first transmitted signal;
obtaining signal energy from said combined output corresponding to said second transmitted signal;
comparing a phase of said first transmitted signal to a phase of said second transmitted signal to generate a phase error indication based upon said obtained signal energies; and
adjusting a phase at which said second signal is transmitted in response to said phase error indication.
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Accused Products
Abstract
In order to align the timing of an overlay base station to the timing of an existing base station, a sync unit is introduced into the system. The sync unit has a first receiver configured to receive a first signal, the first signal having a first CDMA channelization. The first receiver is configured to produce an indication of a timing of the first signal. The sync unit also has a second receiver configured to receive a second signal, the second signal having a second CDMA channelization. The second receiver is configured to produce an indication of a timing of the second signal. The sync unit also has a time error detection unit configured to compare the timing of the first signal and the timing of the second signal to determine a relative timing offset thereof.
11 Citations
20 Claims
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1. A method of overlaying a second CDMA system over a first CDMA system comprising the steps of:
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transmitting a first signal as a first transmitted signal using a first CDMA channelization; transmitting a second signal as a second transmitted signal using a second CDMA channelization, wherein said first and second CDMA channelization share at least a portion of a common frequency spectrum and wherein said first transmitted signal and said second transmitted signal are transmitted as a combined output into a common coverage area; obtaining signal energy from said combined output corresponding to said first transmitted signal; obtaining signal energy from said combined output corresponding to said second transmitted signal; comparing a phase of said first transmitted signal to a phase of said second transmitted signal to generate a phase error indication based upon said obtained signal energies; and adjusting a phase at which said second signal is transmitted in response to said phase error indication. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of overlaying a second CDMA system over a first CDMA system comprising the steps of:
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transmitting a first signal as a first transmitted signal using a first CDMA channelization; transmitting a second signal as a second transmitted signal using a second CDMA channelization, wherein said first and second CDMA channelization share at least a portion of a common frequency spectrum and wherein said first transmitted signal and said second transmitted signal are transmitted as a combined output into a common coverage area; obtaining signal energy from said combined output corresponding to said first transmitted signal; obtaining signal energy from said combined output corresponding to said second transmitted signal; comparing a timing of said first transmitted signal to a timing of said second transmitted signal to generate a timing error indication based upon said obtained signal energies; and
adjusting a timing at which said second signal is transmitted in response to said timing error indication. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification