Adaptive beamforming

• US 10,165,570 B2
• Filed: 04/23/2015
• Issued: 12/25/2018
• Est. Priority Date: 04/23/2015
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sahlin, Henrik, Hashemi, Mona, Cirkic, Mirsad, Berglund, Joel
• Primary Examiner(s): Bednash, Joseph A
• Application Number:
  US14/438,774
• Publication Number:
  US 20160316465A1
• Time in Patent Office: 1,342 Days
• Field of Search: None
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams

Abstract

There is provided mechanisms for adaptive beamforming. A method is performed by a first network device. The method comprises acquiring beamforming information indicating spatial directions in which an identification signal is to be transmitted. The method comprises transmitting the identification signal in a transmission pattern using directional beams in the spatial directions towards second network devices. The identification signal is transmitted such that the identification signal occupies a larger portion of communications resources when transmitted in spatial directions with high second network device presence than in spatial directions with low second network device presence.

Claims

1. A method for adaptive beamforming, the method being performed by a first network device, the method comprising:

acquiring beamforming information indicating a plurality of spatial directions that comprises of a first spatial direction (SD) and a second SD, in which random access signals are received and an identification signal is to be transmitted,

determining a network device density (NDD) of second network devices in the first SD

is greater than a NDD of the second network devices in the second SD; and

in response to determining that the NDD of the second network devices in the first SD is greater than the NDD of the second network devices in the second SD;

i) receiving random access signals from the second network devices in the first SD,

ii) receiving random access signals from the second network devices in the second SD,

wherein the reception of the random access signals from the second network devices is such that random access signals occupies a larger portion of communication resources in the first SD than in the second SD;

iii) transmitting the identification signal in the first SD using a first directional beam, and iv) transmitting the identification signal in the second SD using a second directional beam, wherein the transmission of the identification signal from the first network device is such that identification signal occupies a larger portion of communication resources in the first SD than in the second SD.

2. The method of claim 1, wherein the random access signals are received using a shared random access channel.

3. The method of claim 2, wherein each of the random access signal comprises a random access preamble.

4. The method of claim 3, wherein the first network device transmits to a second network device a random access response in response to the first network device receiving a random access preamble transmitted by the second network device.

5. The method of claim 1, wherein the identification signal comprises a Primary Synchronization Signal (PSS) that corresponds to one of three different physical layer identities.

6. The method of claim 5, wherein the identification signal further comprises a Secondary Synchronization Signal (SSS) that corresponds to one of a plurality of a physical layer cell identity groups.

7. The method of claim 1, wherein the identification signal is transmitted for longer duration in the first SD when compared to the duration in the second SD.

8. The method of claim 1, wherein transmitting the identification signal in the first SD comprises:

transmitting the identification signal in the first SD X number of times within a certain length of time,transmitting the identification signal in the second SD Y number of times within said certain length of time, and X is greater than Y.

9. The method of claim 1, wherein the first directional beam has a narrower beam width than the second directional beam.

10. A first network device, the first network device comprising:

a transmitter;

a receiver;

a persistent storage;

a central processing unit (CPU) coupled to the persistent storage, the transmitter, and the receiver, wherein the first network device is configured to;

acquire beamforming information indicating a plurality of spatial directions that comprises of a first spatial direction (SD) and a second SD, in which random access signals are received and an identification signal is to be transmitted;

determine a network device density (NDD) of second network devices in the first SD

is greater than a NDD of the second network devices in the second SD; and

in response to determining that the NDD of the second network devices in the first SD is greater than the NDD of the second network devices in the second SD;

i) receive random access signals from the second network devices in the first SD,

ii) receive random access signals from the second network devices in the second SD,

wherein the reception of the random access signals from the second network devices is such that random access signals occupies a larger portion of communication resources in first SD than in second SD;

iii) transmit the identification signal in the first SD using a first directional beam, and

iv) transmit the identification signal in the second SD using a second directional beam, wherein the transmission of the identification signal from the first network device is such that identification signal occupies a larger portion of communications resources in the first SD than in the second SD.

11. The first network device of claim 10, wherein the random access signals are received using a shared random access channel.

12. The first network device of claim 11, wherein each of the random access signal comprises a random access preamble.

13. The first network device of claim 12, wherein the first network device transmits to a second network device a random access response in response to the first network device receiving a random access preamble transmitted by the second network device.