초록 ▼

Disclosed are methods for acquiring a forward channel in a point-to-multipoint CDMA system. One method includes the steps of (a) despreading a received CDMA signal with a first pn code that is known to be present in the received CDMA signal and obtaining a first measure of received signal level; (b)

Disclosed are methods for acquiring a forward channel in a point-to-multipoint CDMA system. One method includes the steps of (a) despreading a received CDMA signal with a first pn code that is known to be present in the received CDMA signal and obtaining a first measure of received signal level; (b) despreading the received CDMA signal with a second pn code that is known not to be present in the received CDMA signal and obtaining a second measure of received signal level; and (c) synchronizing to a desired channel using a difference between the first and second signal levels. In this method the first step of despreading despreads a continuously transmitted side-channel, and the step of synchronizing synchronizes to the side-channel. Also, the step of obtaining a first measure of received signal level obtains a correlation peak, and the step of obtaining a second measure of received signal level obtains a correlation null. Preferably, the steps of despreading and obtaining are accomplished iteratively over a range of n first pn code phase states and over a range of n second pn code phase states.

대표청구항 ▼

[ What is claimed is:] [1.] A method for operating a synchronous CDMA communications system, comprising steps of:providing a plurality of subscriber units (SUs);providing at least one radio base unit (RBU) for transmitting a signal comprised of a plurality of first forward channels individual ones o

[ What is claimed is:] [1.] A method for operating a synchronous CDMA communications system, comprising steps of:providing a plurality of subscriber units (SUs);providing at least one radio base unit (RBU) for transmitting a signal comprised of a plurality of first forward channels individual ones of which being intended for receipt by one subscriber unit (SU), and for transmitting at least one second forward channel that is intended for receipt by a plurality of SUs, each of said forward channels being spread with an associated spreading code that has, ideally, an orthogonal relationship to spreading codes of the other forward channels;receiving the transmitted signal at a SU;despreading the received signal using a spreading code associated with the second forward channel to obtain a first measure of received signal energy;despreading the received signal using a null spreading code that is known not to be transmitted by the RBU to obtain a second measure of received signal energy, the null spreading code having, ideally, an orthogonal relationship to the spreading codes of the forward channels; andin the SU, adjusting a phase of the spreading code associated with the second forward channel based on the first and second measures of received signal energy.