Wireless frequency-division-multiple-access direct sequence spread spectrum telephone system

In a digital cordless telephone system having a battery-operated handset for use in conjunction with a compatible base station unit, the handset including a modular controller means, a pseudo-random number generator/decoder means coupled to said controller means for generating a transmit pseudo-random-noise (PN) bit sequence and a receive pseudo-random-noise (PN) bit sequence for use in spread spectrum coding and decoding, a method in said handset for receiving signals from said base station unit comprising:

• b) in a signal pull-in mode following an indication of a valid signal on a signal channel, said valid signal of less than 100% duty cycle in a time frame,
• b-i) sampling in three pairs at intervals substantially evenly spaced over a frame, said pairs being of a PN code phase offset which is a fraction of a chip separation relative to a nominal phase position;
• b-ii) selecting among early samples the early sample having maximum value and among late samples the late sample having maximum value;
• b-iii) determining as an error value from a delay-lock-loop discriminator the difference between the maximum value early sample and the maximum value late sample;
• b-iv) iterating a tracking loop and adjusting phase offset of a local PN bit sequence relative to a matching PN bit sequence on the signal channel as steered by output of said tracking loop;
• and
• b-v) repeating steps b-i) through b-iv) to maintain tracking.

In a digital cordless telephone system having a battery-operated handset for use in conjunction with a compatible base station unit, the handset including a modular controller means, a pseudo-random number generator/decoder means coupled to said controller means for generating a transmit pseudo-random-noise (PN) bit sequence and a receive pseudo-random-noise (PN) bit sequence for use in spread spectrum coding and decoding, a method in said handset for receiving signals from said base station unit comprising:

• c) in a normal signal tracking mode following an indication of a valid signal on a signal channel, said valid signal having less than a 100% duty cycle in a time frame,
• c-i) sampling, at a fractional chip of PN code phase offset, signal values for an early value and a late value relative to nominal phase of said valid signal in the time frame;
• c-ii) determining as an error value from a delay-lock-loop discriminator the difference between the early value and late value;
• c-iii) iterating a tracking loop and adjusting said PN code phase offset relative to a matching PN bit sequence on the signal channel as steered by output of said tracking loop;
• and
• c-iv) repeating steps c-i through c-iii) to track the signals.

In a digital cordless telephone system having a battery-operated handset for use in conjunction with a compatible base station unit, the handset including a modular controller means, a pseudo-random number generator/decoder means coupled to said controller means for generating a transmit pseudo-random-noise (PN) bit sequence and a receive pseudo-random-noise (PN) bit sequence for use in spread spectrum coding and decoding, a method in said handset for receiving signals from said base station unit comprising:

• d) in a standby signal tracking mode following an indication of a valid signal on a signal channel, said valid signal having less than a 100% duty cycle in a time frame,
• d-i) comparing a local PN bit sequence with reception on a signal channel for presence of a matching PN bit sequence about a nominal phase to yield a current received signal strength indication (RSSI) value;
• d-ii) comparing said current RSSI value with a current maximum RSSI value;
• d-iii) upon said current RSSI value exceeding said current maximum RSSI value, substituting said current RSSI value for said current maximum RSSI value, saving an index of location of said then current maximum RSSI value;
• d-iv) incrementing phase of said local PN bit sequence relative to phase of said received signal by a fraction of a chip in phase;
• thereupon
• d-v) repeating steps d-i) through d-iv) for a number of intervals not substantially exceeding a PN code phase uncertainty width of a low-operating duty-cycle discriminator;
• d-vi) determining an output of a low-duty cycle, extended-range delay-lock-loop discriminator;
• d-vii) iterating said delay-lock loop discriminator and adjusting phase offset of a local PN bit sequence relative to a matching PN bit sequence on the signal channel as steered by said error value;
• d-viii) repeating steps d-i) through d-vii) until an incoming call is detected or a call is originated.