Continuous CDPD base station and method of facilitating efficient data transfer

• US 6,370,135 B1
• Filed: 06/07/1995
• Issued: 04/09/2002
• Est. Priority Date: 06/07/1995
• Status: Active Grant

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Gardner, Steven H.
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US08/487,044
• Time in Patent Office: 2,498 Days
• Field of Search: 370/60, 370/60.1, 370/79, 370/94.1, 370/94.2, 370/95.1, 370/95.3, 370/352-356
• US Class Current: 370/352
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6421 Medium of transmission, e.g. fibre, cable, radio, satellite
• CPC Class Codes: H04L 2012/6456 Channel and bandwidth allocation
• CPC Class Codes: H04L 2012/6472 Internet
• CPC Class Codes: H04L 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A multi-mode communication system, including controller, base stations and subscriber stations, where the communication system has the capability of operating either in a packet-switched mode or a circuit-switched mode. The packet-switched mode of operation complies with the existing Cellular Digital Packet Data (CDPD) standard with respect to modulation and higher level protocol, and is designated continuous CDPD mode. This mode of operation is highly cost effective for transfers of relatively small amounts of data. For larger data transfers, the more cost-effective continuous CDPD mode is used. Thus, using this mode, the system is capable of providing superior data rate performance over a vastly greater coverage area than existing circuit-switched modems. Requests for access to continuous CDPD channels are initiated at subscriber stations. This initiation can result from manual intervention by the user of the subscriber station, or can be automatic in response to the amount of data to be transferred, as well as comprising structure for each mode of data transfer used by the service provider.

Claims

1. A communication system arranged to facilitate efficient data transmission, said communication system being constituted by a Cellular Digital Packet Data (CDPD) packet-switched portion, said CDPD packet-switched 5 portion being arranged to facilitate communication for a plurality of wireless subscriber stations using a plurality of Mobile Data Base Stations (MDBS) controlled by at least one Mobile Data Intermediate System (MD-IS), said system further comprising:

(a) a continuous CDPD data portion distributed over a plurality of CDPD mobile data base stations;

(b) means for requesting conversion of a particular data transmission from said CDPD packet-switched portion to said continuous CDPD data portion; and

(c) means for allocating a continuous CDPD channel for said particular data transmission.

2. A communication system of claim 1, wherein said means for requesting operates responsive to an amount of data in said particular data transmission.

3. The communication system of claim 2, wherein a request for conversion is initiated at a wireless subscriber station.

4. The communication system of claim 3, further comprising an analog cellular portion arranged to facilitate communication for a plurality of said wireless subscriber station using a plurality of base stations controlled by a Mobile Telephone Switching Office (MTSO).

5. The communication system of claim 4, wherein said analog cellular portion comprises an Advanced Mobile Phone Service (AMPS) system.

6. The communication system of claim 5, wherein said CDPD packet-switched portion comprises means for carrying out constant envelope modulation, and

said continuous CDPD data portion comprise means for carrying out constant envelope modulation where both said means for carrying out constant envelope modulation are identical to each other.

7. The communication system of claim 6, wherein said continuous CDPD portion comprises at least one dedicated sniffer/modem/transceiver (SNODEM) module located in each said MDBS of said CDPD packet-switched portion.

8. The communication system of claim 7, wherein said dedicated SNODEM operates on a single assigned channel.

9. The communication system of claim 8, wherein data transmission on each said single assigned channel is not subject to pre-emption by CDPD packet-switched communication.

10. The communication system of claim 9, wherein said means for allocating comprise at least one said dedicated SNODEM and a controller board.

11. The communication system of claim 7, wherein said means for allocating comprise means for scanning for an available channel.

12. The communication system of claim 11, wherein said available channel is selected from among channels available for CDPD packet-switched use.

13. The communication system of claim 12, wherein said means for scanning is located at said dedicated SNODEM.

14. The communications system of claim 13, further comprising a second SNODEM where said first and second SNODEM comprise means for scanning.

15. The communication system of claim 14, wherein said first SNODEM observes forward channel activity of a cell containing said first SNODEM, and said second SNODEM observes reverse channel activity originating from other cells.

16. The communication system of claim 10, wherein said means for allocating further comprise said MD-IS.

17. The communication system of claim 7, wherein said means for allocating comprise said MD-IS, said MTSO and a data link therebetween.

18. The communication system of claim 17, wherein a channel allocated for continuous CDPD operation by said means for allocating is not subject to pre-emption by AMPS communication.

19. The communication system of claim 4, further comprising:

(d) means for distinguishing between CDPD packet data communication and continuous CDPD communication.

20. The communication system of claim 3, wherein said means for requesting conversion operates automatically.

21. The communication system of claim 20, wherein said means for requesting conversion further operate responsive to respective cost data of said CDPD packet data communication and continuous CDPD communication.

22. The communication system of claim 3, wherein said means for requesting conversion are operated manually by a user of a wireless subscriber station.

23. A method of efficient data transmission in a communication system, said communication system including a Cellular Digital Packet Data (CDPD) packet-switched portion, where said CDPD portion is arranged to facilitate communication with a plurality of wireless subscriber stations using a plurality of Mobile Data Base Stations (MDBS) controlled by a Mobile Data Intermediate Section (MD-IS);

said method comprising the steps of;

(a) temporarily designating at least one CDPD packet-switched channel as a continuous CDPD channel not subject to use by CDPD packet-switched mode transmissions;

(b) requesting conversion of a particular data transmission from a CDPD packet-switched mode to a continuous CDPD mode; and

(c) transferring said particular data transmission to said designated continuous CDPD channel and carrying out said particular data transmission in said continuous CDPD mode.

24. The method of claim 23, wherein step (b) is carried out responsive to a determination of data amount in said particular data transmission.

25. The method of claim 24, wherein step (b) is further carried out responsive to a determination of respective cost of data transfer for said CDPD packet-switched mode and said continuous CDPD mode.

26. The method of claim 23, wherein step (b) is carried out automatically.

27. The method of claim 26, wherein step (b) is initiated at a wireless subscriber station.

28. The method of claim 23, further comprising:

(d) placing designations on said particular data transmission to distinguish said particular data transmission from CDPD packet-switched mode transmissions whereby a SNODEM operating in the packet-switched mode cannot receive data with uncorrectable transmission errors from a communication being carried out in said continuous CDPD mode.

29. The method of claim 28, wherein step (d) is carried out by placing a different cover sequence on said continuous CDPD data transmission than is used on said CDPD packet-switched mode transmissions.

30. The method of claim 29, wherein a sync word for said continuous CDPD mode data transmission differs from a sync word of a CDPD packet-switched mode transmission.

31. The method of claim 23, wherein step (c) comprises the sub-step of carrying out constant envelope modulation of said particular data transmission in said continuous CDPD mode.

32. The method of claim 31, wherein step (c) further comprises the sub-step of scanning channels available for packet-switched CDPD communication for an unused channel packet-switched channel for carrying out said particular data transmission in said continuous CDPD mode.

33. The method of claim 31, wherein step (c) comprises the sub-step of carrying out a negotiation between said MD-IS and a MTSO to select a channel dedicated to carrying out said particular data transmission in said continuous CDPD mode.

34. The method of claim 33, wherein said particular data transmission in said continuous CDPD mode is not subject to pre-emption by an AMPS communication.

35. A Cellular Digital Packet Data (CDPD), Mobile Data Base Stations (MDBS) comprising:

(a) a plurality of transceiver cards dedicated to CDPD packet-switched communication;

(b) at least one transceiver card allocated to continuous CDPD communication; and

(c) means for assigning a CDPD data communication to said transceiver card allocated to continuous CDPD data communication,

wherein said means for assigning comprise means for scanning among available CDPD packet-switched channels for a channel to be used as a continuous CDPD channel.

36. The CDPD MDBS of claim 35, wherein said at least one transceiver card includes an RF sniffer, at least one RF transceiver and a modem and said means for scanning comprise said RF sniffer.

37. The CDPD MDBS of claim 36, wherein said at least one transceiver card comprises a second RF sniffer and said second RF sniffer comprises said means for scanning.

38. The CDPD MDBS of claim 37, wherein said first RF sniffer observes forward channel activity of a cell containing said first RF sniffer, and said second RF sniffer observes reverse channel activity originating from other cells.

39. A portable wireless subscriber station comprising:

one or more first circuits permitting Cellular Digital Packet Data (CDPD) packet-switched mode of communications;

one or more second circuits permitting continuous CDPD mode of communications; and

a selection mechanism for selecting between said first and second circuits,

wherein said selection mechanism comprises a subscriber-actuated mechanism for switching between modes.

40. The portable wireless subscriber station of claim 39, wherein said selection mechanism comprise means for automatically determining an amount of data in a data file to be transmitted.

41. The portable wireless subscriber station of claim 40, wherein said selection mechanism further comprise means for correlating respective costs for data transmission in said CDPD packet-switched mode and said continuous CDPD mode.

42. The portable wireless subscriber station of claim 39, further comprising means for distinguishing data transmission in said CDPD packet-switched mode from data transmissions in said continuous CDPD mode.