Method and apparatus for directional radio communication

• US 6,392,595 B1
• Filed: 04/20/2001
• Issued: 05/21/2002
• Est. Priority Date: 11/04/1998
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Networks (Nokia Corporation)
• Inventors: Ylitalo, Juha, Katz, Marcos
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/838,874
• Time in Patent Office: 396 Days
• Field of Search: 342/367, 342/422, 455/562, 455/517, 455/69, 455/25
• US Class Current: 342/367
• CPC Class Codes: H04W 16/00 Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A method of directional radio communication between a first station and a second station comprises the steps of determining from at least one signal received at the first station from the second station which of a plurality of different radio environment types is present between said first and second stations. A signal is transmitted from the first station to the second station with at least one parameter of said transmitted signal being dependent on the determined radio environment type.

Claims

1. A method of directional radio communication between a first station and a second station, at least one parameter of said transmitted signal being dependent on the determined radio environment type, comprising the steps of:

determining from at least one signal received at the first station from the second station which of a plurality of different radio environment types is present between said first and second stations based on the angular spread of the at least one signal received by the first station from the second station, wherein a first radio environment type is determined to be present when the at least one signal received by the first station from the second station has a relatively small angular spread and a second radio environment type is determined to be present when the at least one signal received by the first station from the second station has a relatively large angular spread;

selecting between transmitting a signal from the first station to the second station with a relatively small beam spread and with a relatively large beam spread, wherein a relatively small beam spread is selected when it is determined that the first radio environment type is present, and wherein if it is determined that the first radio environment type is present, the method further comprises the step of determining if the beam spread selected should be increased based on a parameter; and

transmitting a signal from said first station to said second station in dependence on the determined radio environment type and said parameter.

2. A method as in claim 1, wherein if the second radio environment type is determined to be present then a relatively large beam spread is selected for the signal to be transmitted from the first station to the second station.

3. A method as claimed in claim 1, wherein the determining if the beam spread is to be increased step, comprises considering a parameter indicative of the distance between the first and second stations and increasing the beam spread of the signal to be transmitted to the second station if the distance between the first and second stations is relatively small.

4. A method as claimed in claim 3, wherein the beam spread of the signal to be transmitted is increased if the distance between the first and second stations is less than a predetermined threshold.

5. A method as claimed in claim 1, wherein the determining if the beam spread is to be increased step, comprises considering a parameter indicative of the speed of movement of the second station relative to the first station and increasing the beam spread of the signal to be transmitted to the second station if the relative speed is relatively high.

6. A method as claimed in claim 5, wherein the beam spread of the signal to be transmitted is increased if the speed of the second station relative to the first station is greater than a predetermined threshold.

7. A method as claimed in claim 1, wherein the determining if the beam spread is to be increased step, comprises considering a parameter indicative of the relative mobility of the second station relative to the first station and increasing the beam spread of the signal to be transmitted to the second station if the relative mobility is relatively large.

8. A method as claimed in claim 7, wherein the beam spread of the signal to be transmitted is increased if the relative mobility of the second station relative to the first station is greater than a predetermined threshold.

9. A method as claimed in claim 1, wherein said determining if the beam spread is to be increased step comprises considering the height of an antenna array of the first station above the surroundings and if the antenna array is relatively low with respect to the surroundings the beam spread is increased.

10. A method as claimed in claim 1, wherein the determining if the beam spread is to be increased step comprises determining the average angular spread for N previous signals received from the second station by the first station.

11. A method as claimed in claim 9, wherein the signal is transmitted by the first station with a beam spread similar to the same as the average angular spread.

12. A method as claimed in claim 10, wherein the period over which the average is determined takes into account one or more of the following parameters:

distance between the first and second stations;

velocity of the second station with respect to the first station; and

relative mobility of the second station relative to the first station.

13. A method as claimed in claim 2 further comprising the step of, if it is determined that the second radio environment type is present, determining if the beam spread of the signal to be transmitted by the first station is to be decreased.

14. A method as claimed in claim 2, wherein the step of determining if the beam spread of the signal is to be decreased comprises determining two extreme directions of arrival for signals from the second station at the first station for the last N previous signals received by the first station from the second station, and transmitting a signal to the second station with beam spread defined by the two extreme directions of arrival.

15. A method as claimed in claim 13, wherein the step of determining if the beam spread of the signal is to be decreased comprises determining the variance of the angular spread of the previous N signals received by the first station from the second station and transmitting the signal to the second station with a beam spread which is related to the calculated variance.

16. A method as claimed in claim 15, wherein the variance of dominant directions of arrival of N preceding signals is determined.

17. A method as claimed in claim 1 wherein the beam spread of the transmitted signal, is defined by one or more beam directions.

18. A method as claimed in claim 17, wherein the width of the or each beam is variable.

19. A method as claimed in claim 1, wherein the first station is a base transceiver station in a cellular telecommunications network.

20. A method as claimed in claim 19, wherein the second station is a mobile station.

21. A first station for directional radio communication with a second station including transmitting means for transmitting a signal to the second station, at least one parameter of the transmitted signal being dependent on the determined radio environment type, said station comprising:

means for receiving signals from the second station;

means for determining from at least one signal received by the first station from the second station which of a plurality of different radio environment types is, in use, present between said first and second stations based on the angular spread of the signal received by said received means, wherein when a signal from the second station is received by said receiving means with a relatively small angular spread, it is determined by said determining means that the radio environment is of a first type and if a signal from the second station is received by said receiving means with a relatively large annular spread, it is determined that the radio environment is of a second type;

means for selecting between transmitting a signal from said first station to said second station with a relatively small beam spread and with a relatively large beam spread, wherein said means for selecting is operable to select a relatively small beam spread when it is determined that the first radio environment type is present;

means for determining, when it is determined that the first radio environment type is present, if the beam spread selected should be increased based on a parameter of the received signal; and

a transmitter arranged to transmit a signal from said first station to said second station with a beam spread determined by the determining means.

22. A first station as claimed in claim 21, wherein said determining means is arranged to determine if the angular spread of the signal transmitted by the transmitting means can be decreased if it is determined that the radio environment is of the second type.

23. A first station as claimed in claim 21, wherein the first station is a base transceiver station.