Massive MIMO multi-user beamforming and single channel full duplex for wireless networks

• US 9,813,121 B1
• Filed: 04/22/2017
• Issued: 11/07/2017
• Est. Priority Date: 05/13/2016
• Status: Active Grant

• Current Assignee: RF DSP, Inc.
• Original Assignee: RF DSP, Inc.
• Inventors: Liang, Ping
• Primary Examiner(s): Nooristany, Sulaiman
• Application Number:
  US15/494,496
• Publication Number:
  US 20170331526A1
• Time in Patent Office: 199 Days
• Field of Search: None
• CPC Class Codes: H04B 1/1018 noise filters connected between the power supply and the receiver suppression or limitation of noise from electric apparatus H04B15/00; demodulation H03D; ripple filters H02M1/14; filters in general 95G, H03H; power supplies H04B1/1607
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• 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: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

This invention presents a method and apparatuses for wireless networking comprising one or more BS with N_bs antennas; two or more SCs in the range of a BS where a SC has N_sc antennas, uses N_sc1≦N_sc antennas for communication with a BS and uses N_sc2≦N_sc antennas for communication with one or more UEs; at the same time a BS transmitting DL signals to K SCs using multi-user transmit BF in a frequency channel, a SC simultaneously transmitting DL signals to one or more UEs in its range using the same frequency channel; and, at the same time a BS receiving UL signals from K SCs using multi-user receive BF in a frequency channel, a SC simultaneously receiving UL signals from one or more UEs in its range using the same frequency channel. Furthermore, beamforming using antennas on the SCs is performed to reduce the inter-SC interferences.

Claims

1. A method for wireless networking comprising one or more base stations (BSs) with N_bs antennas;

two or more small cells (SCs) in the range of each of said one or more base stations, wherein each of said two or more small cells has N_sc antennas, and uses N_sc1≦

N_sc antennas for communication with said BS in the range and uses N_sc2≦

N_sc antennas for communication with one or more user equipment (UEs);

which comprises;

at the same time a BS selected from said one or more BSs is transmitting downlink (DL) signals to K SCs selected from said two or more SCs in the range thereof using multi-user transmit beamforming (BF) in a DL frequency channel where K>

1 and N_bs≧

KN_sc1, a SC selected from said K SCs receiving the DL signals from said BS and simultaneously transmitting DL signals to one or more UEs in its range using the same DL frequency channel in a single-channel full duplex mode and performing cancelation of an interference from the transmission of the DL signals to the one or more UEs on the receiving of the DL signals from the BS, and canceling the remaining interference after an Analog to Digital Converter in digital baseband using digital signal processing; and

at the same time said BS selected from said one or more BSs is receiving uplink (UL) signals from said K SCs using multi-user receive BF in a UL frequency channel where K>

1 and N_bs≧

KN_sc1, said SC selected from said K SCs transmitting the UL signals to said BS simultaneously receiving UL signals from said one or more UEs in its range using the same UL frequency channel in a single-channel full duplex mode and performing cancelation of an interference from the transmission of the UL signals to the BS on the receiving of the UL signals from the one or more UEs, and canceling the remaining interference after an Analog to Digital Converter in digital baseband using digital signal processing.

2. The method in claim 1, wherein said BS selected from said one or more BSs selects the number of BS antennas to use such that said number is sufficiently larger than the total number of antennas on said K SCs communicating with said BS using the same frequency resource to match the throughput of the link between said BS and said K SCs with the sum throughput of said K SCs.

3. The method in claim 1 further comprising canceling self-interference using a RF filter that generates a RF cancelation signal to subtract the self-interference from the received RF signal prior to the Low Noise Amplifier of the receiver.

4. The method of claim 1 further comprising canceling self-interference that exists after the Low Noise Amplifier by generating an analog cancelation signal in analog baseband or IF (intermediate frequency) prior to Analog to Digital Converter.

5. The method in claim 1, further comprising using the same antennas on at least one of said K SCs simultaneously for DL and UL with N_sc=N_sc1=N_sc2 for said at least one of said K SCs.

6. The method in claim 1 further comprising transmitting DL signals from said SC selected from said K SCs to at least one of said one or more UEs in its range using a first frequency channel at one time slot and receiving UL signals from said at least one UE(s) using the same first frequency channel at another time slot in a Time-Division Duplexing network.

7. The method in claim 6 further comprising the BS selected from said one or more BSs estimating the channel matrix of the channels between the BS and the two or more SCs H_b-s by having the SCs transmits UL pilot signals, and using channel reciprocity to estimate the downlink channel from the BS to the SCs.

8. The method in claim 1 further comprising simultaneously, via SCs, transmitting DL signals to one or more UEs in its range using a first frequency channel and receiving UL signals from said one or more UEs using a second frequency channel in a Frequency-Division Duplexing network.

9. The method in claim 1 further comprising suppressing the interference of the BS to SC transmission to the SC to UE transmission by adding a null space pro-coding matrix to the BS to SC transmission.

10. The method in claim 9 further comprising

estimating the interference power P_i at a UE under the multi-user beamforming (MUBF) transmission of the BS,

comparing the estimated P_i with a threshold α

, and

if the interference is larger than a required value α

, the BS including this UE in the interference suppression pre-coding matrix.

11. The method in claim 1 further comprising allocating a different frequency segment or set of subcarriers to each BS-SC-UE(s) path that is causing significant inter-SC interference.

12. The method of claim 1 further comprising beamforming in DL from BS to UEs or UL from UEs to BS using the antennas of one or more SCs to reduce the inter-SC interference.

13. The method of claim 12 wherein the beamforming pre-coding computation is performed at one or more of the SCs.

14. The method of claim 12 wherein the beamforming pre-coding computation is performed at the BS.

15. The method in claim 1 further comprising using both wired backhaul to some SCs and wireless backhaul to other SCs in a wireless network.

16. The method in claim 1 further comprising using one frequency channel for wireless link between a BS and a SC and a different frequency channel for wireless link between a SC and a UE.

17. An apparatus for wireless networking comprising a baseband and radio frequency components supporting N_sc antennas,

wherein the apparatus uses N_sc1≦

N_sc antennas for communication with a BS with N_bs antennas and uses N_sc2≦

N_sc antennas for communication with one or more UEs in its range;

wherein the apparatus communicates wirelessly with a BS;

wherein, at the same time a BS is transmitting DL signals to the apparatus using multi-user transmit BF in a DL frequency channel where N_bs≧

KN_sc1, the apparatus operates in single-channel full duplex mode by simultaneously transmitting DL signals to said one or more UEs in its range using the same DL frequency channel and receiving the DL signals from the said BS and performing cancelation of the interference from the transmission of the DL signals to the one or more UEs on the receiving of the DL signals from the said BS, and canceling the remaining interference after an Analog to Digital Converter in digital baseband using digital signal processing; and

at the same time the BS is receiving UL signals from the apparatus using multi-user receive BF in a UL frequency channel where N_bs≧

KN_sc1, the apparatus operates in single-channel full duplex mode by simultaneously receiving UL signals from the one or more UEs in its range using the same UL frequency channel and transmitting the UL signals to said BS, and performing cancelation of the interference from the transmission of the UL signals to said BS on the receiving of the UL signals from the one or more UEs, and canceling the remaining interference after an Analog to Digital Converter in digital baseband using digital signal processing.