CDMA mobile communication system and communication method

• US 6,269,088 B1
• Filed: 08/01/1996
• Issued: 07/31/2001
• Est. Priority Date: 08/10/1995
• Status: Expired due to Term

• Current Assignee: FIPA Frohwitter Intellectual Property AG
• Original Assignee: Hitachi, Ltd.
• Inventors: Doi, Nobukazu, Yano, Takashi, Masui, Hironari, Ohgoshi, Yasuo
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US08/690,819
• Time in Patent Office: 1,825 Days
• Field of Search: 370/329, 370/335, 370/336, 370/342, 370/258, 370/461, 370/345, 370/343, 370/347, 370/348, 370/320, 370/321, 370/330, 370/443, 370/441, 370/442, 370/436, 370/437 , 370/450, 370/322, 370/337, 370/323, 370/344, 375/200, 375/206, 375/207, 375/367, 375/130, 375/135, 375/136, 375/134, 375/140, 375/142, 375/143, 375/146, 375/147, 375/148, 375/152, 455/517, 455/509, 455/510, 455/515, 455/516
• US Class Current: 370/335
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/2637 for logical channel control
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/1263 Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
• CPC Class Codes: H04W 74/085 collision avoidance

Abstract

A radio communication system having a base station and a plurality of radio terminals, wherein each radio terminal having a transmission request transmits a reservation packet at arbitrary timing through a reservation channel in accordance with a CDMA scheme, and the base station assigns a traffic channel and a time slot to be used to each radio terminal requesting a reservation through a reply packet outputted onto a reply channel. On the reservation channel, a short spreading code corresponding to a matched filter is applied.

Claims

1. A communication method in a code division multiple access (CDMA) mobile communication system wherein radio channels between a base station and plurality of mobile terminals include a plurality of traffic channels used for transmitting upward data packets directed from the mobile terminals to the base stations and for transmitting downward data packets directed from the base station to the mobile terminals, a reservation channel used for transmitting reservation packets each indicative of a traffic channel assignment request from a mobile terminal to the base station, and a reply channel used for transmitting reply packets each indicative of a traffic channel through which data is to be transmitted and received from the base station to a mobile terminal, and said reservation, reply and traffic channels are assigned unique spreading codes, respectively, said method comprising the steps of:

transmitting a reservation packet from a mobile terminal having a request for data transmission onto said reservation channel;

transmitting a reply packet onto said reply channel from the base station to specify a traffic channel and a time slot to be used to each mobile terminal which has transmitted said reservation packet; and

transmitting a data packet from each mobile terminal which has transmitted said reservation packet in the specified time slot on the traffic channel specified by said reply packet, wherein;

said each mobile terminal having a request for data transmission applies a spreading code unique to said reservation channel having a period shorter than a spreading code applied to the spreading of a data packet to be transmitted on said traffic channel in order to apply spread-spectrum to said each reservation packet, and

said base station processes a received signal using a matched filter in which said spreading code unique to said reservation channel is set, said base station utilizing the periodicity of said spreading code to separate outputs of said matched filter into a plurality of signal trains corresponding to respective reservation packets.

2. A communication method according to claim 1, further comprising the steps of:

providing a local address shorter than unique address information assigned to each mobile terminal from said base station to said each mobile terminal,

wherein said base station sets a local address in a destination address field of said reply packet and transmits said reply packet; and

receiving said reply packet including a local address given to each mobile terminal in the destination address field by said each mobile terminal.

3. A communication method according to claim 2, further comprising the steps of:

providing a link number shorter than address information unique to each mobile terminal from said base station to said each mobile terminal;

wherein said each mobile terminal transmits a data packet including said link number as a destination address onto a traffic channel.

4. A communication method according to claim 2, wherein said base station uses the reply packet for giving a local address to a mobile terminal to specify a reply channel through which the mobile terminal is to perform receiving operations.

5. A communication method in a radio communication system wherein a base station and a plurality of radio terminals communicate through a reservation channel, a reply channel and a plurality of traffic channels formed in accordance with a code division multiple access (CDMA) scheme in radio channels, said method comprising the steps of:

transmitting reservation packets onto said reservation channel from said respective radio terminals requesting data transmission;

separating a plurality of reservation packet signals having partially overlapped portions on a time axis, received through said reservation channel, corresponding to reservation packets;

performing a receiving process on the reservation packets;

transmitting from said base station a reply packet for specifying a CDMA traffic channel and a time slot to be used to each radio terminal which is a source of each received reservation packet through said reply channel; and

transmitting a single data packet in the specified time slot on the CDMA traffic channel specified by said reply packet from said each radio terminal,

wherein said single data packet from said each radio terminal is transmitted to said base station in response to a respective reply packet.

6. A communication method according to claim 5, further comprising the steps of:

after transmitting, from said base station to a radio terminal identified by a destination address in a data packet received from said traffic channel, said reply packet for specifying a traffic channel and a time slot to be used by said radio terminal for reception through said reply channel, transmitting said received packet in said specified time slot on said specified traffic channel; and

receiving said data packet in said specified time slot on said traffic channel specified by said reply packet at the radio channel terminal which is the destination of said reply packet.

7. A radio terminal apparatus for communicating with a base station through radio channels, comprising:

means for transmitting a reservation packet processed with a spreading code unique to a reservation channel to said base station;

means for receiving a reply packet processed with a spreading code unique to a reply channel, transmitted from said base station at a predetermined time slot synchronized with said base station; and

means for transmitting and receiving a single data packet processed with a spreading code unique to a particular Code Division Multiple Access (CDMA) traffic channel at a predetermined time slot on said particular CDMA traffic channel specified by said reply packet,

wherein said single data packet is transmitted to said base station in response to a respective reply packet.

8. A base station for communicating with a plurality of radio terminals, each having a unique address, using spread-spectrum packets through a reservation channel, a reply channel and a plurality of Code Division Multiple Access (CDMA) traffic channels, each of said channels corresponding to a unique spreading code, comprising:

means for receiving reservation packet signals each for requesting a traffic channel access transmitted by the plurality of radio terminals through said reservation channel, and separating said reservation packet signals into individual reservation packets for a receiving process;

means for transmitting, through said reply channel, a reply packet for specifying a traffic channel and a time slot to be used to a radio terminal which is a source of said reservation packet; and

means for receiving a single data packet transmitted from a radio terminal or for transmitting a single data packet to a radio terminal in each time slot on a CDMA traffic channel,

wherein said single data packet is transmitted to said base station in response to a respective reply packet.

9. A mobile communication system, comprising:

a base station; and

a plurality of mobile terminals,

wherein radio channels between the base station and the plurality of mobile terminals include a plurality of traffic channels used for transmitting upward data packets directed from said mobile terminals to said base station and for transmitting downward data packets directed from said base station to said mobile terminals, a reservation channel used for transmitting reservation packets each indicative of a traffic channel assignment request from a mobile terminal to said base station, and a reply channel used for transmitting reply packets each indicative of a Code Division Multiple Access (CDMA) traffic channel through which data is transmitted and received from said base station to a mobile terminal, each of said reservation, reply and traffic channels being assigned a unique spreading code, and each spreading code to said reservation and reply channels is common to a plurality of mobile stations in accordance with a CDMA scheme,

wherein said each mobile terminal comprises first means for transmitting a reservation packet onto said reservation channel when a request for data transmission is issued, and second means for transmitting and receiving a single data packet in a time slot specified by a reply packet transmitted from said base station through said reply channel;

wherein said single data packet transmitted from said terminal is transmitted to said base station in response to a respective reply packet; and

wherein said base station comprises third means for separating a plurality of reservation packet signals having partially overlapped portions on a time axis, received through said reservation channel, into reservation packets and performing a receiving process on said reservation packets, and fourth means for transmitting a reply packet for specifying a traffic channel and a time slot to be used, through said reply channel, to each mobile terminal which is a source of each received reservation packet.

10. A mobile communication system, comprising:

a base station; and

a plurality of mobile terminals,

wherein radio channels between the base station and the plurality of mobile terminals include a plurality of traffic channels used for transmitting upward data packets directed from said mobile terminals to said base stations and for transmitting downward data packets directed from said base station to said mobile terminals, to said mobile terminals, a reservation channel used for transmitting reservation packets each indicative of a traffic channel assignment request from a mobile terminal to said base station, and a reply channel used for transmitting reply packets each indicative of a traffic channel through which data is transmitted and received from said base station to a mobile terminal, each of said reservation, reply and traffic channels being assigned a unique spreading code in accordance with a code division multiple access (CDMA) scheme, wherein;

said each mobile terminal comprises first means for transmitting a reservation packet onto said reservation channel when a request for data transmission is issued, and second means for transmitting and receiving a data packet in a time slot specified by a reply packet transmitted from said base station through said reply channel; and

said base station comprises third means for separating a plurality of reservation packet signals having partially overlapped portions on a time axis, received through said reservation channel, into reservation packets and performing a receiving process on said reservation packets, and fourth means for transmitting a reply packet for specifying a traffic channel and a time slot to be used, through said reply channel, to each mobile terminal which is a source of each received reservation packet,

said first means of said each mobile terminal applies a spreading code unique to the reservation channel having a period shorter than a spreading code applied to a data packet transmitting through the traffic channel by said second means to spread said each reservation packet, and

said third means of said base station processes a received signal with a matched filter in which said spreading code unique to said reservation channel is set, and separates an output of said matched filter into a plurality of signal trains corresponding to said packets utilizing the periodicity of said spreading code.

11. A communication method in a code division multiple access (CDMA) mobile communication system for performing communication between a base station and a plurality of mobile stations, said method comprising the steps of:

transmitting a reservation packet indicative of a traffic channel assignment request from a mobile terminal having a request for data transmission onto a reservation channel assigned a spreading code common to said plurality of mobile stations;

transmitting a reply packet onto a reply channel assigned a spreading code which is common to said plurality of mobile stations from said base station to specify a CDMA traffic channel and a transmitting timing to be used to each mobile terminal which has transmitted said reservation packet; and

transmitting a single data packet from a mobile terminal which has transmitted said reservation packet at said transmitting timing on said CDMA traffic channel which is assigned a unique spreading code and specified by said reply packet,

wherein said single data packet from said mobile terminal is transmitted to said base station in response to a respective reply packet.

12. A base station for communicating with a plurality of radio terminals, each having a unique address, using spread-spectrum packets through a reservation channel, a reply channel, and a plurality of traffic channels, each of said channels corresponding to a unique spreading code, said base station comprising:

means for receiving reservation packet signals each requesting traffic channel access transmitted by the plurality of radio terminals through said reservation channel, and separating said reservation packet signals into individual reservation packets for a receiving process by grouping peak values of a correlation value between said reservation packet signal and said spreading code assigned to said reservation channel at a time interval equal to a symbol;

means for transmitting through said reply channel a reply packet for specifying a Code Division Multiple Access (CDMA) traffic channel and a time slot to be used to a radio terminal which is a source of a reservation packet; and

means for receiving a single data packet transmitted from a radio terminal or for transmitting a single data packet to a radio terminal in each time slot on a CDMA traffic channel,

wherein said single data packet received from said radio terminal is transmitted to said base station in response to a respective reply packet.

13. A communication method in a code division multiple access (CDMA) mobile communication system for performing communication between a base station and a plurality of mobile stations, said method comprising the steps of:

transmitting a reservation packet indicative of a traffic channel assignment request from a mobile terminal having a request for data transmission onto a reservation channel assigned a spreading code common to said plurality of mobile stations;

transmitting a reply packet onto a reply channel assigned a spreading code common to said plurality of mobile stations from said base station to specify a Code Division Multiple Access (CDMA) traffic channel and a time slot to be used to each mobile terminal which has transmitted said reservation packet; and

transmitting a single data packet from said mobile terminal which has transmitted said reservation packet in the specified time slot on the CDMA traffic channel which is assigned a unique spreading code and specified by said reply packet,

wherein said single data packet from said each radio terminal is transmitted to said base station in response to a respective reply packet.

14. A communication method according to claim 13, wherein said each mobile terminal requests the transmission of a plurality of data packets through a single reservation packet.

15. A communication method according to claim 13, wherein said base station continuously transmits a pilot signal including a synchronization signal component through a pilot channel or through said reply channel such that each mobile terminal identifies a time slot on said traffic channel based on said received pilot signal.

16. A packet communication system, comprising:

a base station;

a plurality of terminals;

wherein packet communication is executed such that reservation packets are transmitted from said plurality of terminals to said base station through a reservation channel using Code Division Multiple Access (CDMA), and a reply from said base station sets a start timing of packet communication, said pocket communication is made through CDMA traffic channels provided between said base station and said plurality of terminals,

wherein said packet communication includes transmission of a single data packet from a terminal to said base station in response to a respective reply packet.

17. The system according to claim 16, wherein a traffic channel assignment request is made by said reservation packets.

18. The system according to claim 17, wherein said reservation packets are used to request specifying of packet transmission timing.

19. The system according to claim 16, wherein said plurality of terminals spread reservation packets by using a same spread code.

20. A packet communication system, comprising:

a base station;

a plurality of terminals; and

reservation channels provided between said base station and said plurality of terminals;

wherein packet communication is executed by transmitting reservation packets from said plurality of terminals to said base station utilizing Code Division Multiple Access (CDMA), and, upon receiving a reply to said reservation packets from said base station, data packets are transmitted through CDMA traffic channels provided between said base station and said plurality of terminals,

wherein said packet communication includes transmission of a single data packet from a terminal to said base station in response to a respective reply packet.

21. A packet communication system, comprising:

a base station; and

a terminal which transmits a reservation packet to said base station via a reservation channel utilizing Code Division Multiple Access (CDMA) and, upon receiving a reply from said base station, transmits data packets to said base station via a CDMA traffic channel,

wherein said terminal transmits a single data packet to said base station in response to a respective reply packet.

22. A terminal, comprising:

a Code Division Multiple Access (CDMA) transmitter/receiver unit which transmits a reservation packet to a reservation channel using CDMA and transmits a data packet to a CDMA traffic channel;

a reservation channel constructing circuit;

a traffic packet constructing circuit which is activated in accordance with a timing set by a reply to said reservation packet,

wherein said CDMA transmitter/receiver unit transmits a single data packet to said traffic channel base station in response to a respective reply packet.

23. The terminal according to claim 22, wherein said reservation packet is used to request a traffic channel assignment.

24. The terminal according to claim 23, wherein said reservation packet is used to request specifying of packet transmission timing.

25. A base station, comprising:

a Code Division Multiple Access (CDMA) transmitter/receiver unit which receives a reservation packet using CDMA from a reservation channel and receives a data packet from a CDMA traffic channel;

a reply packet constructing unit which creates a reply packet with respect to said reservation packet,

wherein a timing of transmitting a data packet from a terminal is set by said reply packet,

wherein said CDMA transmitter/receiver unit receives a single data packet from said transmitted in response to a respective reply packet.

26. The base station according to claim 25, wherein said reply is used to notify a traffic channel assignment.

27. The base station according to claim 26, wherein said reply is used to specify a packet transmission timing.

28. A communication method in a radio communication system wherein a base station and a plurality of radio terminals communicate in accordance with a code division multiple access (CDMA) scheme in radio channels, said method comprising the steps of:

transmitting a reservation packet using CDMA from one of said plurality of radio terminals requesting data transmission;

receiving a reply packet using CDMA from the base station, corresponding to the reservation packet, in the one radio terminal;

transmitting a data packet using CDMA from the one radio terminal in response to the reply packet,

wherein a single data packet is transmitted in response to a single reply packet.

29. The method according to claim 28, wherein a single reservation packet is transmitted for a single data packet.

30. The method according to claim 29, wherein a single data packet has a constant length not longer than a time slot.

31. The method according to claim 30, wherein a call setup process between the one radio terminal and the base station is performed in advance, and

wherein the one radio terminal transmits a plurality of reservation packets and data packets after the call setup process.