Method and apparatus for transmitting and receiving signals using two classes of channels

• US 5,615,409 A
• Filed: 09/25/1995
• Issued: 03/25/1997
• Est. Priority Date: 09/27/1993
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Gudmundson, Bjorn, Forssen, Ulf
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/533,104
• Time in Patent Office: 547 Days
• Field of Search: 455/25, 455/33.1, 455/33.2, 455/33.3, 455/33.4, 455/34.1, 455/53.1, 455/54.1, 455/56.1, 379/59, 379/60, 342/373, 342/383
• US Class Current: 455/440
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 72/563 of the wireless resources

Abstract

A method and apparatus for transmitting and receiving signals in a base station with an antenna array in a cellular communication system. The available communication channels are divided into a plurality of classes. The base station transmits signals to the mobile station in a first class of channels in a wide antenna lobe. The position of a mobile station can then be determined from signals received at the base station from the mobile station. After the position of the mobile station has been determined, the base station can transmit signals to and receive signals from the mobile station in a second class channel with a narrow antenna lobe.

Claims

1. A method for transmitting and receiving signals at a base station with an antenna array in a cellular communication system, comprising the steps of:

dividing available communication channels into a plurality of classes;

transmitting signals to a plurality of mobile stations in a first class of channels with a wide antenna lobe created by said antenna array, wherein said first class of channels is used to transmit broadcast information to an entire cell and to receive initial access signals from mobile stations, said first class of channels is also used for enabling mobile stations to measure the downlink signal strength transmitted from adjacent base stations and is used for handover access during handovers between base stations;

determining position of a first mobile station from signals received from said first mobile station;

transmitting signals to said first mobile station in a second class of channels with a narrow antenna lobe created by said antenna array when the position of said mobile is determined; and

receiving signals from said first mobile station with adjustable lobe widths on both channel classes.

2. A method according to claim 1, wherein the position of said first mobile station is determined by:

measuring the power level of signals received from said first mobile station; and

determining a proper antenna lobe for a newly connected mobile station.

3. A method according to claim 1, wherein said base station assigns said mobile station to a channel in said second class of channels after the position of said mobile station is determined to be above a predetermined level of certainty.

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

transmitting and receiving signals at a mobile station on a channel in said second class of channels; and

performing handover measurements of signals received at said mobile station on said first class of channels.

5. A method according to claim 1, wherein at least one control channel and a minority of traffic channels belong to the first class of channels.

6. A method according to claim 1, wherein said second class of channels has a smaller reuse distance than said first class of channels.

7. A method according to claim 1, wherein said second class of channels has more than one user for each channel.

8. A method according to claim 1, wherein said second class of channels has variable antenna lobe widths.

9. A method according to claim 8, wherein the base station gradually reduces the antenna lobe width of a second class channel assigned to a mobile station as the base station gradually determines the position of said mobile station.

10. A communication system with at least one base station having an antenna array, comprising;

means for transmitting signals from a base station to a plurality of mobile stations on a plurality of classes of channels;

means for receiving signals from a plurality of mobile stations at a base station on a plurality of classes of channels;

means for determining a position of a mobile station from said received signals, wherein said base station transmits signals in a first class of channels with a wide antenna lobe created by said antenna array and said base station transmits signals in a second class of channels with a narrow antenna lobe created by said antenna array when the position of said mobile station has been determined, wherein said first class of channels is used to transmit broadcast information to an entire cell and to receive initial access signals from mobile stations, said first class of channels is also used for enabling mobile stations to measure the downlink signal strength transmitted from adjacent base stations and is used for handover access during handovers between base stations.

11. A cellular communication system according to claim 10, wherein said first class of channels is used for handover between base stations.

12. A cellular communication system according to claim 11, wherein a mobile station contains means for transmitting and receiving signal on a channel in said second class of channels and means for measuring handover measurements on a channel in said first class of channels.

13. A cellular communication system according to claim 12, said mobile station further comprising means for transmitting and receiving signals on a channel in said first class of channels.

14. A cellular communication system according to claim 10, wherein said position determining means comprises:

means for determining a power level of a signal from said mobile station; and

means for determining an antenna lobe for a said mobile station.

15. A cellular communication system according to claim 10, wherein said base station assigns said mobile station to a channel in said second class of channels after the position of said mobile is determined to be above a predetermined level of certainty.

16. A cellular communication system according to claim 10, wherein at least one control channel and a minority of traffic channels belong to the first class of channels.

17. A cellular communication system according to claim 10, wherein said second class of channels has a smaller reuse distance than said first class of channels.

18. A cellular communication system according to claim 10, wherein said second class of channels has more than one user for each channel.

19. A cellular communication system according to claim 10, wherein said second class of channels has variable antenna lobe widths.

20. A cellular communication system according to claim 19, wherein the base station gradually reduces the antenna lobe width of a class two channel assigned to a mobile station as the base station gradually determines the position of said mobile station.

21. A communication system according to claim 10, wherein mobile stations in traffic mode can be connected to a traffic channel belonging to either the first class or the second class of channels while the mobile stations simultaneously use first class channels to extract downlink control messages and to perform signal strength measurements on adjacent base stations.