Common packet channel
View Patent ↗An improvement to a code-division-multiple-access (CDMA) system employing spread-spectrum modulation, with the CDMA system having a base station (BS) and a plurality of remote stations. The base station has a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver. A remote station has an RS-spread-spectrum transmitter and an RS-spread-spectrum receiver. The BS transmitter transmits a broadcast common-synchronization channel, which includes a frame-timing signal. The broadcast common-synchronization channel has a common chip-sequence signal, which is common to the plurality of remote stations. In response to the RS-spread-spectrum receiver receiving the broadcast common-synchronization channel, and determining frame timing from the frame-timing signal, an RS-spread-spectrum transmitter transmits an access-burst signal. The BS-spread-spectrum transmitter, responsive to the BS-spread-spectrum receiver receiving the access-burst signal, transmits an acknowledgment signal. In response to the first RS-spread-spectrum receiver receiving the acknowledgment signal, the first RS-spread-spectrum transmitter transmits a spread-spectrum signal having data.
1. A method of wireless transmission of information, comprising:
(a) transmitting a signal comprising a single preamble randomly selected from among a group of available preambles, at a power level;
(b) determining if number of preamble transmissions has reached a limit;
(c) determining if an acknowledgement corresponding a preamble transmission is received from a base station;
(d) if the number of preamble transmissions has not reached the limit and there has been no receipt of a corresponding acknowledgement, repeating step (a) at a higher power level and repeating steps (b) and (c);
(e) ceasing transmitting of the signal, upon any determination at (b) that the number of preamble transmissions has reached the limit; and
(f) upon any determination at (c) that a corresponding acknowledgement is received from the base station, initiating transmission of information over a wireless spread-spectrum uplink channel to the base station.
2. The method of claim 1 , further comprising receiving information over a wireless spread-spectrum downlink channel from the base station.
3. The method of claim 2 , wherein the information received from the base station comprises any of packet data and power control information.
4. The method of claim 1 , wherein the initiating of transmission of information comprises:
randomly selecting a collision detection symbol from a number of possible collision detection symbols;
transmitting the collision detection symbol at a power level the same as the power level used for the preamble transmission immediately preceding the receipt of the corresponding acknowledgement; and
if a collision detection acknowledgment corresponding to the collision detection symbol is received, transmitting the information over the spread-spectrum uplink channel to the base station.
5. The method of claim 4 , wherein the information transmitted to the base station comprises at least one of packet data and power control information.
6. The method of claim 4 , further comprising receiving information over a wireless spread-spectrum downlink channel from the base station.
7. The method of claim 6 , wherein the information received from the base station comprises any of packet data and power control information.
8. The method of claim 7 , wherein during each repetition of transmitting at (a), power level of transmission of the pilot signal increases.
9. The method of claim 1 , wherein during each transmitting at (a) the signal further comprises a pilot signal.
10. The method of claim 1 , further comprising:
receiving a frame timing signal from the base station;
wherein each transmitting at (a) involves transmitting the signal comprising the single preamble in a time slot randomly selected from among a plurality of possible time slots defined in relation to the received frame timing signal.
11. A method of wireless transmission of information, comprising:
(a) transmitting a signal comprising a single preamble randomly selected from among a group of available preambles, at a power level;
(b) determining if number of preamble transmissions has reached a limit;
(c) determining if an acknowledgement corresponding a preamble transmission is received from the base station;
(d) if the number of preamble transmissions has not reached the limit and there has been no receipt of a corresponding acknowledgement, repeating step (a) at a higher power level, transmitting a pilot symbol, and repeating steps (b) and (c);
(e) ceasing transmitting of the signal, upon any determination at (b) that the number of preamble transmissions has reached the limit;
(f) upon any determination at (c) that a corresponding acknowledgement is received from the base station, randomly selecting a collision detection symbol from among a number of possible collision detection symbols;
(h) transmitting the collision detection symbol at a power level the same as the power level used for the preamble transmission immediately preceding the receipt of the corresponding acknowledgement;
(g) if a collision detection acknowledgment corresponding to the collision detection symbol is received, transmitting information over a wireless spread-spectrum uplink channel to the base station; and
(h) receiving information over a wireless spread-spectrum downlink channel from the base station.
12. The method of claim 11 , wherein:
the information transmitted over the wireless spread-spectrum uplink channel to the base station comprises at least one of packet data and power control information; and
the information received over the wireless spread-spectrum downlink channel from the base station comprises at least one of packet data and power control information.
13. The method of claim 11 , further comprising:
receiving a frame timing signal from the base station;
wherein each transmitting at (a) comprises transmitting the signal comprising the single selected preamble in a time slot randomly selected from among a plurality of possible time slots defined in relation to the received frame timing signal.
14. A spread-spectrum wireless mobile station, comprising:
a spread-spectrum transmitter;
a spread-spectrum receiver; and
a controller coupled to the spread-spectrum receiver for responding to received signals and coupled for controlling the spread-spectrum transmitter, such that in operation the wireless mobile station performs steps comprising:
(a) transmitting a signal comprising a single preamble randomly selected from among a group of available preambles, at a power level;
(b) determining if number of preamble transmissions has reached a limit;
(c) determining if an acknowledgement corresponding a preamble transmission is received from a base station;
(d) if the number of preamble transmissions has not reached the limit and there has been no receipt of a corresponding acknowledgement, repeating step (a) at a higher power level and repeating steps (b) and (c);
(e) ceasing transmitting of the signal, upon any determination at (b) that the number of preamble transmissions has reached the limit; and
(f) upon any determination at (c) that a corresponding acknowledgement is received from the base station, initiating transmission of information over a wireless spread-spectrum uplink channel to the base station.
15. The mobile station of claim 14 , wherein the initiating of transmission of information comprises:
randomly selecting a collision detection symbol from a number of possible collision detection symbols;
transmitting the collision detection symbol at a power level the same as the power level used for the preamble transmission immediately preceding the receipt of the corresponding acknowledgement; and
if a collision detection acknowledgment corresponding to the collision detection symbol is received, transmitting the information over the spread-spectrum uplink channel to the base station.
16. The mobile station of claim 14 , wherein at least during a repetition of (a), the signal transmitted further comprises a pilot signal following the selected preamble.
17. The mobile station of claim 14 , wherein:
the controller is for controlling operation of the remote station for performing the additional step comprising receiving a frame timing signal from the base station; and
each transmitting of the signal at (a) involves transmitting the signal comprising the single preamble in a time slot randomly selected from among a plurality of possible time slots defined in relation to the received frame timing signal.
18. A base band processor for use in a spread-spectrum wireless remote station, comprising:
an acknowledgment detector for detecting an acknowledgment in received spread-spectrum signals;
a data and control processor, for detecting and processing data and control information contained in received spread-spectrum signals;
a encoder, for encoding data;
a preamble generator for generating preambles;
a multiplexer for multiplexing the encoded data and the preambles;
a packet formatter, coupled to the multiplexer, for formatting the multiplexed data and preambles into packets; and
a controller coupled to the acknowledgment detector for controlling the preamble generator, the multiplexer and the packet formatter, such that in operation the base band processor performs steps comprising:
(a) transmitting a signal comprising a single preamble randomly selected from among a group of available preambles, at a power level;
(b) determining if number of preamble transmissions has reached a limit;
(c) determining if an acknowledgement corresponding a preamble transmission is received from a base station;
(d) if the number of preamble transmissions has not reached the limit and there has been no receipt of a corresponding acknowledgement, repeating step (a) at a higher power level and repeating steps (b) and (c);
(e) ceasing transmitting of the signal, upon any determination at (b) that the number of preamble transmissions has reached the limit; and
(f) upon any determination at (c) that a corresponding acknowledgement is received from the base station, initiating transmission of information over a wireless spread-spectrum uplink channel to the base station.
19. The base band processor of claim 18 , wherein the initiating of transmission of information comprises:
randomly selecting a collision detection symbol from a number of possible collision detection symbols;
transmitting the collision detection symbol at a power level the same as the power level used for the preamble transmission immediately preceding the receipt of the corresponding acknowledgement; and
if a collision detection acknowledgment corresponding to the collision detection symbol is received, transmitting the information over the spread-spectrum uplink channel to the base station.
20. The base band processor of claim 18 , wherein at least during a repetition of (a), the signal transmitted further comprises a pilot signal following the selected preamble.
21. The base band processor of claim 18 , wherein:
the controller is for controlling operation of the base band processor for performing the additional step comprising receiving a frame timing signal from the base station; and
each transmitting of the signal at (a) involves transmitting the signal comprising the single preamble in a time slot randomly selected from among a plurality of possible time slots defined in relation to the received frame timing signal.
22. The base band processor of claim 18 , further comprising:
a spread-spectrum modulator for modulating formatted packets from the packet formatter for transmission over the wireless uplink channel; and
a spread-spectrum demodulator for demodulating the received spread-spectrum signals.
23. The base band processor of claim 22 , further comprising an interleaver for interleaving encoded data from the encoder and supplying interleaved encoded data to the packet formatter.