Rapid acquisition spreading codes for spread-spectrum communications

A subscriber unit for a multiple access, spread-spectrum communication system that receives and processes a code-division multiplexed (CDM) signal which modulates a carrier signal in a radio frequency (RP) channel to reconstruct a transmitted information signal assigned to a subscriber comprising:

• receiving means for receiving the modulated carrier signal from the RF channel and for demodulating the CDM signal from the carrier signal;
• a subscriber unit controller;
• modem processing means comprising:
• a) global pilot code acquisition means comprising a global pilot code generation means for providing a global pilot code signal;
• a plurality of global pilot code-phase delayed correlation means for correlating the global pilot code signal with the CDM signal to produce a despread global pilot code signal, the code phase of the global pilot signal being changed responsive to an acquisition signal;
• and means for determining whether the despread global pilot signal is present to produce an acquisition signal;
• b) a plurality of message code generators which produce a plurality of message code signals synchronized to the global pilot code signal;
• and
• c) global pilot code tracking means for producing an error signal responsive to the acquisition signal;
• d) means for adjusting the global pilot code signal in phase, responsive to the error signal in a sense to produce the acquisition signal which corresponds to an increased Level of the despread global pilot signal;
• and
• e) a plurality of message signal acquisition means for providing a plurality of despread receive message signals, each acquisition means including a plurality of message signal correlators, each message signal correlator correlating a respective one of the message code signals with the CDM signal to produce a respective despread receive message signal.

A bearer channel modification system for a multiple access spread-spectrum communication system including a plurality of information signals each having several different channel rates which information signals are transmitted as a plurality of message code channels over an Radio Frequency (RF) channel as a Code Division Multiplexed (CDM) signal, the system comprising

• means for providing a plurality of call type signals corresponding to the information signal rates for the information signals;
• wherein each of the plurality of message code channels supports a predetermined information channel rate;
• a transmitter including a first information channel mode modification means responsive to the call type signal for changing the combination of the information signal from a first one of the message code signals to a second one of the message code signals which second message code signal supports a different information channel rate than the first message code signal;
• and
• a receiver including a second information channel mode modification means responsive to the call type signal for changing a received information signal from the first message code signal to the second message code signal to support the different information channel rate.

A multiple access spread-spectrum communication system for dynamically changing the transmission rate of a plurality of information signals received simultaneously over telecommunication lines by a base station and transmitted to a subscriber through a plurality of spread-spectrum message channels, the system comprising

• a) a base station, connected to a remote call-processor which provides a call type signal identifying an information signal rate of the respective information signal and a conversion method for the respective information signal;
• comprising:
• a system channel controller which assigns each of the information signals and call type signals to a respective spread-spectrum message channel;
• first information channel mode modification means connected to the system channel controller and responsive to the call type signal for changing the combination of the respective information signal from one spread-spectrum message channel to another pre-determined spread-spectrum message channel which supports a different information channel rate;
• and
• b) a subscriber unit comprising:
• a plurality of despreading means, each of the despreading means for recovering a respective one of the information signals and a respective one of the call type signals from a respective one of the spread-spectrum message channels;
• second information channel mode modification means responsive to the call type signal for reassigning the despreading means to another determined despreading means corresponding to a different spread spectrum channel wherein a different information signal rate is supported;
• and
• a signal conversion means responsive to the call type signal for selectively converting the despread information signal into a digital data signal.

A method for capacity management in a spread-spectrum communication system including a base station and a plurality of subscriber units (SUs), wherein the base station transmits to the SUs a plurality of spread-spectrum channels including an access channel having a traffic access value which is received by each SU, and a respective plurality of message channels;

• and wherein each SU transmits to the base station an assigned channel having a power alarm value and a SU message channel, the method comprising the steps of:
• measuring, by the base station, a transmit power level of the access channel and the plurality of message channels;
• comparing, by the base station, the transmit power level to a first predetermined power value to produce a power comparison output value;
• blocking transmission of an assigned channel and a respective SU message channel, responsive to the power comparison output value, by setting the traffic access value to a first predetermined value when the transmit power level is equivalent to or greater than the predetermined value, wherein one SU of the plurality of SUs, responsive to the traffic access value, does not transmit the assigned channel and the SU message channel;
• measuring, by each ones of the SUs, a transmit power level of the respective SU for the respective assigned channel and message channel;
• comparing by each ones of the SUs the transmit power level of the respective SU to a second predetermined value;
• and
• indicating a maximum power condition to the base station, by one SU, by setting the respective power alarm value to an alarm condition value when the transmit power level of the SU is equivalent to or greater than the second predetermined value;
• and
• blocking transmission of the respective assigned channel and SU message channel of each ones of the SUs, by the base station responsive to the alarm condition value, by setting the traffic access value to the first predetermined value.

A method for conserving capacity of an ISDN wireless link of a spread-spectrum communication system including a first spread-spectrum transceiver and a second spread-spectrum transceiver, said first spread-spectrum transceiver receiving a digital data signal including a predetermined flag pattern corresponding to an idle period and transferring the digital data signal to said second transceiver as a spread spectrum signal, and said second spread-spectrum transceiver receiving the spread spectrum signal and delivering the digital data signal, the method comprising the steps of:

• delaying, by the first transceiver, the digital data signal to form a delayed digital data signal;
• monitoring the digital data signal to detect the predetermined flag pattern;
• transmitting the delayed digital data signal as the spread-spectrum signal to the second transceiver;
• suspending transmission of the delayed digital data signal when the flag pattern is present;
• detecting, by the second transceiver, the absence of the delayed digital data signal;
• and
• inserting the predetermined flag pattern in the delivered digital data signal.