Methods and apparatus for wireless network connectivity

• US 7,450,543 B2
• Filed: 08/13/2002
• Issued: 11/11/2008
• Est. Priority Date: 08/14/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Corson, M. Scott, Laroia, Rajiv, Li, Junyi
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US10/217,791
• Publication Number:
  US 20030035410A1
• Time in Patent Office: 2,282 Days
• Field of Search: 370/331, 370/350, 370/503, 375/260, 375/356, 455/436, 455/502
• US Class Current: 370/331
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/185 using make before break
• CPC Class Codes: H04W 52/0203 in the radio access network or backbone network of wireless communication networks
• CPC Class Codes: H04W 52/0212 managed by the network, e.g. network or access point is master and terminal is slave
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods and apparatus which allow a wireless terminal (302) to simultaneously maintain connections with multiple base stations (304, 306) are described. Each wireless terminal (302) is capable of supporting multiple separate timing and/or other control loops one, for each base station connection thereby allowing the connections to operate independently and in parallel. Different control signals and/or data are transmitted on each connection that is established with a base station (302, 306). In this manner base stations (302, 306) receive different data allowing for asynchronous data transmission. The data received by the base stations (302, 306) can be supplied to a wired asynchronous network (308) without the need to combine the received data prior to supplying it to the wired network (308). The communications techniques of the invention can be used to implement soft handoffs without the need to duplicate data transmissions to multiple base stations.

Claims

1. A mobile communications device for communicating, in parallel with a plurality of base stations each operating with different signal timing, the communications device comprising:

a plurality of receiver timing synchronization loops capable of establishing, in parallel, timing synchronization with said plurality of base stations, said receiver timing synchronization loops being used to adjust receiver timing in said mobile communications device.

2. The mobile communications device of claim 1, wherein said plurality of receiver timing synchronization loops are receiver symbol timing loops.

3. The mobile communications device of claim 1, further comprising:

control means for controlling the transmission of different portions of a data file to different base stations at the same time.

4. The mobile communications device of claim 1, further comprising:

a plurality of signal separation circuits, a different signal separation circuit being coupled to each one of said plurality of receiver timing synchronization loops for separating signals corresponding to different base stations, such that signals corresponding to different base stations will be processed by different receiver timing synchronization loops.

5. The mobile communications device of claim 4, further comprising:

an analog receiver circuit for receiving an input analog signal corresponding to signals transmitted by multiple base stations; and

an analog to digital converter coupled to said analog receiver circuit and said signal separation circuits.

6. The mobile communications device of claim 5, wherein the signals transmitted by each base station are orthogonal frequency division multiplexed signals;

and

wherein said signal separation circuits are filters which filter out the tones corresponding to base stations which are not to be processed by the receiver timing synchronization loop to which the particular signal separation circuit is coupled.

7. The apparatus of claim 1, wherein each of said plurality of receiver timing synchronization loops corresponds to a communications link with a different base station, said base stations being asynchronous, the apparatus further comprising:

memory storing different sets of transmitter and receiver synchronization parameters, different sets of transmitter and receiver synchronization parameters corresponding to communications links with different base stations.

8. A mobile communications device for communicating, in parallel with a plurality of base stations each operating with different signal timing, the communications device comprising:

a plurality of timing synchronization loops capable of establishing, in parallel, timing synchronization with said plurality of base stations; and

wherein said plurality of timing synchronization loops include receiver timing synchronization loops and transmitter timing synchronization loops, a plurality of said transmitter timing synchronization loops and a plurality of said receiver timing synchronization loops being used in parallel, at least one receiver timing synchronization loop and one transmitter timing synchronization loop being used for each base station with which said mobile communications device establishes a communications connection.

9. The mobile communications device of claim 8, further comprising:

a plurality of encoder circuits, a different one of said plurality of encoder circuits being coupled to each of said plurality of transmitter timing synchronization loops.

10. The mobile communications device of claim 9, wherein each of said plurality of encoders encodes data corresponding to connections to different base stations.

11. The mobile communications device of claim 10, further comprising:

a digital combining device coupled to said plurality of transmitter timing synchronization loops for combining data processed by said transmitter timing synchronization loops to thereby generate a combined digital signal.

12. The mobile communications device of claim 11, further comprising:

a digital to analog converter for converting said combined digital signal into an analog transmission signal; and

an analog transmission circuit for transmitting said analog transmission signal.

13. The mobile communications device of claim 8, further comprising:

a plurality of decoder circuits, a different one of said plurality of decoder circuits being coupled to each of said plurality of receiver timing synchronization loops.

14. The mobile communications device of claim 13, wherein each of said plurality of decoder circuits decodes data corresponding to connections to different base stations.

15. The mobile communications device of claim 8, further comprising:

a plurality of signal separation circuits, a different signal separation circuit being coupled to each one of said plurality of receiver timing synchronization loops for separating signals corresponding to different base stations, such that signals corresponding to different base stations will be processed by different receiver timing synchronization loops.

16. The mobile communications device of claim 15, further comprising:

an analog receiver circuit for receiving an input analog signal corresponding to signals transmitted by multiple base stations; and

an analog to digital converter coupled to said analog receiver circuit and said signal separation circuits.

17. The mobile communications device of claim 16, wherein the signals transmitted by each base station are orthogonal frequency division multiplexed signals;

and

wherein said signal separation circuits are filters which filter out the tones corresponding to base stations which are not to be processed by the receiver timing synchronization loop to which the particular signal separation circuit is coupled.

18. The mobile communications device of claim 8, wherein said plurality of receiver timing synchronization loops are receiver symbol timing loops.

19. A method of operating a wireless terminal to interact with a plurality of base stations including a first base station and a second base station, comprising:

performing a first receiver timing synchronization operation to synchronize data signal receiver timing with the first base station; and

performing a second receiver timing synchronization operation to synchronize data signal receiver timing with the second base station, the first and second timing synchronization operations being performed independently and in parallel.

20. The method of claim 19,

wherein said step of performing first timing synchronization operation includes receiving timing control signals from the first base station over a first control link;

and

wherein said step of performing second timing synchronization operation includes receiving timing control signals from the second base station over a second control link.

21. The method of claim 20, wherein said first and second timing synchronization operations are symbol timing synchronization operations.

22. The method of claim 20, further comprising:

transmitting first data to the first base station; and

in parallel with transmitting the first data to the first base station, transmitting second data to the second base station.

23. The method of claim 22, wherein said first and second data are different parts of a single data file.

24. The method of claim 23, wherein said data file is one of an E-mail file, an image file and a text file.

25. The method of claim 24,

wherein said first data is stored in a first data packet and said second data is stored in a second data packet;

and

wherein transmission of said second data packet to said second base station begins during transmission of said first data packet to said first base station.

26. The method of claim 25, further comprising:

ceasing the transmission of data to said first base station after transmission of said first data packet is completed while continuing to transmit data to said second base station.

27. The method of claim 19, further comprising:

receiving an analog signal, said analog signal including signals from said first and second base stations;

performing an analog to digital conversion operation on said analog signal;

separating signals corresponding to said first and second base stations by processing the output of said analog to digital conversion operation; and

performing independent frequency correction operations on the separated signals received from said first and second base stations.

28. A method of implementing a handoff between base stations of a communications system, the method comprising:

communicating with a first base station;

establishing a connection with a second base station;

transmitting, in parallel, different data in different communications signals which are transmitted in parallel to said first and second base stations, respectively; and

using different symbol transmission start times when transmitting symbols representing at least portions of said first and second data packets to said first and second base stations.

29. The method of claim 28,

wherein said different data in different communications signals are different data packets representing packets of digital data;

and

wherein said step of transmitting different data to said first and second base stations includes transmitting a first data packet to said first base station and transmitting a second data packet to said second base station, each of the first and second data packets including different data from a set of data to be transmitted.

30. The method of claim 29, wherein said set of data to be transmitted is one of an E-mail message, a voice message, and a text message.

31. The method of claim 28, wherein said set of data to be transmitted is one of an E-mail message, a voice message, and a text message.

32. The method of claim 31, further comprising:

monitoring the quality of the connections with the first and second base stations; and

ceasing to transmit data to the lower quality connection.

33. The method of claim 31, further comprising:

monitoring the quality of the connections with the first and second base stations; and

changing the base station to which data is transmitted when the quality of the connection being used to transmit data becomes worse than the quality of the data connection to the base station to which data was not being transmitted.

34. The method of claim 28, wherein transmitting, in parallel, different data in different communications signals includes transmitting data corresponding to different data packets of a file, at least one data packet corresponding to said file being communicated to the first base station not being communicated to the second base station.

35. The method of claim 34, wherein said at least one data packet is being transmitted to the first base station while transmission of another data packet corresponding to the file is initiated to said second base station.

36. A method of implementing a communications system, the method comprising:

providing a plurality of base stations for interacting with a mobile communications device;

operating at least a first and second base station in said plurality of base stations to receive, in parallel, different data from said mobile communications device to be transmitted over a wired asynchronous communications network; and

operating the first and second base stations to supply said received data to said wired asynchronous network; and

operating the first and second base stations to perform independent asynchronous symbol timing synchronization operations with said mobile communications device.

37. The method of claim 36, wherein said different data includes at least a portion of a first data packet transmitted by said first base station and a second data packet transmitted by said second base station.

38. The method of claim 37, wherein said first and second data packets correspond to different portions of at least one of an E-mail message, a voice message and a text message being transmitted by said wireless terminal.

39. The method of claim 38, wherein said communications system is an OFDM communications system.

40. A mobile communications device for communicating, in parallel with a plurality of base stations each operating with different signal timing, the communications device comprising:

analog to digital signal conversion means; and

a plurality of receiver timing synchronization means capable of establishing, in parallel, timing synchronization with said plurality of base stations, said receiver timing synchronization means being used to adjust receiver timing in said mobile communications device, said plurality of receiver timing conversion means being coupled to a digital signal output of said analog to digital signal conversion means.

41. A mobile communications device for communicating, in parallel with a plurality of base stations each operating with different signal timing, the communications device comprising:

a plurality of timing synchronization means capable of establishing, in parallel, timing synchronization with said plurality of base stations; and

wherein said plurality of timing synchronization means each include receiver timing synchronization means and transmitter timing synchronization means, a plurality of said transmitter timing synchronization means and a plurality of said receiver timing synchronization means being used in parallel, at least one receiver timing synchronization means and one transmitter timing synchronization means being used for each base station with which said mobile communications device establishes a communications connection.

42. A computer readable medium embodying computer executable instructions for controlling a communications device to implement a communications method of interacting with a plurality of base stations including a first base station and a second base station, the method comprising:

performing a first receiver timing synchronization operation to synchronize data signal receiver timing with the first base station; and

performing a second receiver timing synchronization operation to synchronize data signal receiver timing with the second base station, the first and second timing synchronization operations being performed independently and in parallel.

43. A device including a processor configured to implement a method of interacting with a plurality of base stations including a first base station and a second base station, the processor being configured to:

perform a first receiver timing synchronization operation to synchronize data signal receiver timing with the first base station; and

perform a second receiver timing synchronization operation to synchronize data signal receiver timing with the second base station, the first and second timing synchronization operations being performed independently and in parallel.

44. A computer readable medium embodying computer executable instructions for controlling a communications device to implement a method of implementing a handoff between base stations of a communications system, the method comprising:

communicating with a first base station;

establishing a connection with a second base station

transmitting, in parallel, different data in different communications signals which are transmitted in parallel to said first and second base stations, respectively; and

using different symbol transmission start times when transmitting symbols representing at least portions of said first and second data packets to said first and second base stations.

45. A device including a processor configured to implement a method of implementing a handoff between base stations of a communications System, the processor being configured to control the device to:

communicate with a first base station;

establish a connection with a second base station

transmit, in parallel, different data in different communications signals which are transmitted in parallel to said first and second base stations, respectively; and

use different symbol transmission start times when transmitting symbols representing at least portions of said first and second data packets to said first and second base stations.