Sub-Sampling Antenna Elements

• US 20160380363A1
• Filed: 06/20/2016
• Published: 12/29/2016
• Est. Priority Date: 06/25/2015
• Status: Active Grant

• Current Assignee: Airspan IP Holdco LLC (Airspan Networks Holdings, Inc.)
• Original Assignee: Airspan Networks Inc.
• Inventors: Logothetis, Andrew
• Granted Patent: US 10,070,325 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F16M 11/06 allowing pivoting
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073
• CPC Class Codes: G01S 19/53 Determining attitude
• CPC Class Codes: G01S 3/043 Receivers
• CPC Class Codes: G01S 3/14 Systems for determining direction or deviation from predetermined direction aerial arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00; combinations of different interacting aerial units for giving a desired directional characteristic H01Q21/29; aerials or aerial systems providing at least two radiation patterns H01Q25/00
• CPC Class Codes: G01S 5/0247 Determining attitude
• CPC Class Codes: H01Q 1/02 Arrangements for de-icing; Arrangements for drying-out ; Arrangements for cooling; Arrangements for preventing corrosion
• CPC Class Codes: H01Q 1/1207 for fastening a rigid aerial element
• CPC Class Codes: H01Q 1/1228 on a boom
• CPC Class Codes: H01Q 1/1257 using the received signal strength
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 21/00 Antenna arrays or systems arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 25/002 : providing at least two patterns of different beamwidth; Variable beamwidth antennas
• CPC Class Codes: H01Q 25/005 : providing two patterns of opposite direction; back to back antennas H01Q25/004 takes precedence
• CPC Class Codes: H01Q 3/02 : using mechanical movement of antenna or antenna system as a whole
• CPC Class Codes: H01Q 3/04 : for varying one co-ordinate of the orientation
• CPC Class Codes: H01Q 3/10 : to produce a conical or spiral scan
• CPC Class Codes: H01Q 3/12 : using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems
• CPC Class Codes: H01Q 3/24 : varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/26 : varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/2611 : Means for null steering; Adaptive interference nulling
• CPC Class Codes: H01Q 3/36 : with variable phase-shifters
• CPC Class Codes: H04B 7/0456 : Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0617 : for beam forming
• CPC Class Codes: H04B 7/0621 : Feedback content
• CPC Class Codes: H04B 7/0691 : using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0695 : using beam selection
• CPC Class Codes: H04B 7/0817 : with multiple receivers and antenna path selection
• CPC Class Codes: H04B 7/086 : using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04B 7/0874 : using subgroups of receive antennas
• CPC Class Codes: H04B 7/088 : using beam selection
• CPC Class Codes: H04L 41/0806 : for initial configuration or provisioning, e.g. plug-and-play
• CPC Class Codes: H04L 41/0816 : the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 43/0829 : Packet loss
• CPC Class Codes: H04L 67/34 : involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 67/52 : specially adapted for the location of the user terminal
• CPC Class Codes: H04W 16/28 : using beam steering
• CPC Class Codes: H04W 24/02 : Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/08 : Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 24/10 : Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/0236 : radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 28/0268 : using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] negotiating SLA or negotiating QoS H04W28/24
• CPC Class Codes: H04W 28/0284 : detecting congestion or overload during communication monitoring arrangements H04L43/00
• CPC Class Codes: H04W 28/24 : Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 4/50 : Service provisioning or reconfiguring
• CPC Class Codes: H04W 40/22 : using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 48/06 : based on traffic conditions
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/542 : using measured or perceived quality
• CPC Class Codes: H04W 84/02 : Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
• CPC Class Codes: H04W 84/045 : using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 88/04 : adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 88/08 : Access point devices
• CPC Class Codes: H05K 7/20 : Modifications to facilitate cooling, ventilating, or heating

Abstract

An antenna apparatus for use in a wireless network and method of operating such an antenna apparatus are provided. The antenna apparatus has omnidirectional antenna elements and RF chains, where there are fewer RF chains than omnidirectional antenna elements. A subset of the omnidirectional antenna elements are coupled to the RF chains and sampling circuitry coupled to the RF chains samples the signals received by the subset of the omnidirectional antenna elements. This forms part of a signal detection process in which different subsets of the omnidirectional antenna elements are iteratively coupled to the RF chains. A signal sample spatial covariance matrix for the omnidirectional antenna elements is constructed from the signals sampled by the sampling circuitry at each iteration and a beamforming algorithm applied to the signal sample spatial covariance matrix parameterises the signals received by the omnidirectional antenna elements.

Claims

1. An antenna apparatus comprising:

a plurality of omnidirectional antenna elements;

a plurality of RF chains, wherein a number of the plurality of RF chains is less than a number of the plurality of omnidirectional antenna elements;

selective connection circuitry to couple a subset of the plurality of omnidirectional antenna elements to the plurality of RF chains;

sampling circuitry coupled to the plurality of RF chains to sample signals received by the subset of the plurality of omnidirectional antenna elements; and

signal detection circuitry to control a signal detection process comprising the selective connection circuitry iteratively coupling subsets of the plurality of omnidirectional antenna elements to the plurality of RF chains and the signal detection circuitry constructing a signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry at each iteration,

and the signal detection circuitry is configured to apply a beamforming algorithm to the signal sample spatial covariance matrix to parameterise the signals received by the plurality of omnidirectional antenna elements.

2. The antenna apparatus as claimed in claim 1, wherein the signal detection circuitry has a configuration to construct the signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry by:

accumulating zero lag auto-correlation values for the signals sampled at each antenna element as a summation;

normalising the summation with respect to a number of iterations performed to generate an averaged power value for the antenna; and

populating diagonal elements of the signal sample spatial covariance matrix with the averaged power value.

3. The antenna apparatus as claimed in claim 1, wherein the signal detection circuitry has a configuration to construct the signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry by:

populating off-diagonal elements of the signal sample spatial covariance matrix with zero lag cross-correlation values for the signals sampled at respective antenna elements.

4. The antenna apparatus as claimed in claim 3, wherein the off-diagonal elements of the signal sample spatial covariance matrix populated with zero lag cross-correlation values for the signals sampled at respective antenna elements are one of:

upper triangular elements or lower triangular elements of the signal sample spatial covariance matrix, and wherein the signal detection circuitry has a configuration to construct the signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry by;

conjugating, index-swopping and copying the zero lag cross-correlation values used to populate the upper triangular elements or the lower triangular elements of the signal sample spatial covariance matrix to the lower triangular elements or the upper triangular elements respectively.

5. The antenna apparatus as claimed in claim 1, wherein the signal detection circuitry has a configuration to construct the signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry by:

accumulating elements of the signal sample spatial covariance matrix as a combination of a previously constructed signal sample spatial covariance matrix and elements calculated from the signals sampled by the sampling circuitry in a current instance of the signal detection process.

6. The antenna apparatus as claimed in claim 5, wherein the signal detection circuitry is capable of applying at least one time-evolution factor when combining the previously constructed signal sample spatial covariance matrix and the elements calculated from the signals sampled by the sampling circuitry in the current instance of the signal detection process.

7. The antenna apparatus as claimed in claim 6, wherein the at least one time-evolution factor is applied as a first selected weighting for the previously constructed signal sample spatial covariance matrix elements and a second selected weighting for the elements calculated from the signals sampled by the sampling circuitry in the current instance of the signal detection process, wherein the first selected weighting and the second selected weighting sum to one.

8. The antenna apparatus as claimed in claim 1, wherein the signal detection circuitry is responsive to completion of the signal sample spatial covariance matrix to apply the beamforming algorithm to the signal sample spatial covariance matrix to generate at least one direction of arrival estimate for the signals received by the plurality of omnidirectional antenna elements.

9. The antenna apparatus as claimed in claim 8, wherein the signal detection circuitry is capable of using the beamforming algorithm to generate at least one received signal strength indication for the signals received by the plurality of omnidirectional antenna elements.

10. The antenna apparatus as claimed in claim 8, wherein the signal detection circuitry is capable of using the beamforming algorithm to generate an indication of a number of sources present in the signals received by the plurality of omnidirectional antenna elements.

11. The antenna apparatus as claimed in claim 1, comprising a uniform circular array comprising the plurality of omnidirectional antenna elements.

12. The antenna apparatus as claimed in claim 1, wherein the antenna apparatus is capable of participating in a passive sounding procedure coordinated with at least one further antenna apparatus, wherein during the passive sounding procedure the antenna apparatus and the at least one further antenna apparatus do not transmit, and the signal detection process forms part of the passive sounding procedure.

13. The antenna apparatus as claimed in claim 1, wherein the antenna apparatus is capable of participating in an active sounding procedure coordinated with at least one further antenna apparatus, wherein during the active sounding procedure one of the group formed by the antenna apparatus and the at least one further antenna apparatus transmits a predetermined signal and others of the group formed by the antenna apparatus and the at least one further antenna apparatus sample the predetermined signal, and the signal detection process forms part of the sampling performed in the active sounding procedure.

14. A method of operating an antenna apparatus comprising the steps of:

selectively coupling a subset of a plurality of omnidirectional antenna elements of the antenna apparatus to a plurality of RF chains of the antenna apparatus, wherein a number of the plurality of RF chains is less than a number of the plurality of omnidirectional antenna elements;

operating sampling circuitry coupled to the plurality of RF chains to sample signals received by the subset of the plurality of omnidirectional antenna elements;

iteratively coupling subsets of the plurality of omnidirectional antenna elements to the plurality of RF chains;

constructing a signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry at each iteration;

applying a beamforming algorithm to the signal sample spatial covariance matrix to parameterise the signals received by the plurality of omnidirectional antenna elements.

15. An antenna apparatus comprising:

a plurality of omnidirectional antenna element means;

a plurality of RF chain means, wherein a number of the plurality of RF chain means is less than a number of the plurality of omnidirectional antenna element means;

means for selectively coupling a subset of the plurality of omnidirectional antenna element means to the plurality of RF chain means;

means for operating sampling circuitry coupled to the plurality of RF chains to sample signals received by the subset of the plurality of omnidirectional antenna elements;

means for iteratively coupling subsets of the plurality of omnidirectional antenna elements to the plurality of RF chains;

means for constructing a signal sample spatial covariance matrix for the plurality of omnidirectional antenna elements from the signals sampled by the sampling circuitry at each iteration; and

means for applying a beamforming algorithm to the signal sample spatial covariance matrix to parameterise the signals received by the plurality of omnidirectional antenna elements.