Systems and methods for wireless communication with per-beam signal synchronization

• US 10,541,850 B2
• Filed: 10/31/2016
• Issued: 01/21/2020
• Est. Priority Date: 10/31/2016
• Status: Active Grant

• Current Assignee: Southeast University
• Original Assignee: Southeast University
• Inventors: Gao, Xiqi, You, Li, Wang, Wenjin
• Primary Examiner(s): Sefcheck, Gregory B
• Application Number:
  US15/744,909
• Publication Number:
  US 20190013983A1
• Time in Patent Office: 1,177 Days
• Field of Search: None
• CPC Class Codes: H04B 7/01 Reducing phase shift
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 56/005 compensating for timing error by adjustment in the receiver

Abstract

Signal transmitting/receiving electronic devices or terminals in the present disclosure are configured to conduct per-beam signal synchronization in massive MIMO communication with a signal receiving/transmitting device or base station. During the massive MIMO communication, the devices or terminals are configured to transmit/receive signals via a set of beams to or from the signal receiving/transmitting device or base station. For beam domain signal of each individual beam of the plurality beams, the devices or terminals are configured to determine target time adjustments based on time shifts of the beam domain signals induced by multipath effect and target frequency adjustments based on frequency offsets of the beam domain signals induced by the Doppler effect; adjust time independent variables of the beam domain signals by the time adjustments; and adjust frequency independent variables of the beam domain signals by the frequency adjustments. Further, per-beam synchronized BDMA massive MIMO transmission method is disclosed, which provides a solution to efficient and reliable wireless communications with high mobility and/or high carrier frequency.

Claims

1. A signal receiving electronic device, comprising:

at least one storage medium including a set of instructions for per-beam signal synchronization; and

at least one processor in communication with the at least one storage medium, wherein when executing the set of instructions, the processor is directed to conduct a wireless communication with a signal transmitting device via beamforming, during which the at least one processor is directed to;

receive a beam domain signal via a beam set from the signal transmitting device; and

individually synchronize the beam domain signal in each beam of the beam set, wherein to individually synchronize the beam domain signal, the at least one processor is further directed to, for the beam domain signal of each individual beam of the beam set;

determine a target frequency adjustment based on frequency offset of the beam domain signal when the beam domain signal is transmitted to the signal receiving device; and

adjust at least one frequency independent variable of the beam domain signal by the target frequency adjustment,

wherein the beam domain signal of each beam comprises a plurality of transmission blocks, and wherein to determine the target frequency adjustment, the processor is further directed to;

for each of the plurality of transmission blocks,

determine a candidate minimum frequency adjustment as a minimum frequency offset of the beam domain signal induced to the beam;

determine a candidate maximum frequency adjustment as a maximum frequency offset of the beam domain signal induced to the beam;

determine a lower bound value of the target frequency adjustment as the minimum of the plurality of the candidate minimum frequency adjustments;

determine an upper bound value of the target frequency adjustment as the maximum of the plurality of the candidate maximum frequency adjustments; and

select a value of the target frequency adjustment between the lower bound value and upper bound value.

2. The device of claim 1, wherein to individually synchronize the beam domain signal, the at least one processor is further directed to, for beam domain signal of each individual beam of the beam set:

determine a target time adjustment based on time shift of the beam domain signal when the beam domain signal is transmitted to the signal receiving device; and

adjust at least one time independent variable of the beam domain signal by the target time adjustment.

3. The device of claim 2,

wherein to determine the target time adjustment, the processor is further directed to:

for each of the plurality of transmission blocks, determine a candidate time adjustment as a minimum time shift of the beam domain signal induced to the beam;

determine the target time adjustment as the minimum of the plurality of the candidate time adjustment values.

4. The device of claim 1, wherein each beam in the beam set is a millimeter-wave or Terahertz beam associated with a same frequency.

5. The device of claim 1, wherein the plurality of beams comprises a group of mutually non-overlapping beams.

6. The device of claim 1, wherein the wireless communication comprises a massive multiple-input multiple-output transmission.

7. The device of claim 1, wherein the signal of each beam of the beam set comprises data transmission and pilot training, and the pilot training transmitted from the signal transmitting device to different signal receive devices are not mutually orthogonal.

8. The device of claim 1, wherein the beam domain signal comprises data transmission and pilot training,

the first pilot training of a first beam of the beam set and the first pilot training of a second beam of the plurality of beams are mutually orthogonal.

9. A method for per-beam signal synchronization comprising, during wireless communication between a signal transmitting device and a signal receiving device:

receiving, by the signal receiving device, a beam domain signal via a beam set from the signal transmitting device; and

individually synchronizing, by the signal receiving device the beam domain signal in each beam of the beam set, wherein the individually synchronizing of the beam domain signal further comprises, for the beam domain signal of each individual beam of the plurality beams;

determining a target frequency adjustment based on frequency offset of the beam domain signal when the beam domain signal is transmitted to the signal receiving device; and

adjusting at least one frequency independent variable of the beam domain signal by the target frequency adjustment,

wherein the beam domain signal of each beam comprises a plurality of transmission blocks, and wherein the determining of the target frequency adjustment further comprises;

for each of the plurality of transmission blocks,

determining a candidate minimum frequency adjustment as a minimum frequency offset of the beam domain signal induced to the beam;

determining a candidate maximum frequency adjustment as a maximum frequency offset of the beam domain signal induced to the beam;

determining a lower bound value of the target frequency adjustment as the minimum of the plurality of the candidate minimum frequency adjustments;

determining an upper bound value of the target frequency adjustment as the maximum of the plurality of the candidate maximum frequency adjustments; and

selecting a value of the target frequency adjustment between the lower bound value and upper bound value.

10. The method of claim 9, wherein the individually synchronizing of the beam domain signal further comprises, for beam domain signal of each individual beam of the plurality beams:

determining a target time adjustment based on time shift of the beam domain signal when the beam domain signal is transmitted to the signal receiving device; and

adjusting at least one time independent variable of the beam domain signal by the target time adjustment.

11. The method of claim 10,

wherein the determining of the target time adjustment comprises:

for each of the plurality of transmission blocks, determining a candidate time adjustment as a minimum time shift of the beam domain signal induced to the beam;

determining the target time adjustment as the minimum of the plurality of the candidate time adjustment values.

12. The method of claim 9, wherein each of the plurality of beams is a millimeter-wave or Terahertz beam associated with a same frequency.

13. The method of claim 9, wherein the plurality of beams comprises a group of mutually non-overlapping beams.

14. The method of claim 9, wherein the wireless communication comprises a massive multiple-input multiple-output transmission.

15. The method of claim 9, wherein the signal of each beam of the beam set comprises data transmission and at least one first pilot signal for pilot training, and

the at least one first pilot signal is not mutually orthogonal with second pilot signals transmitted from the signal transmitting device to another signal receiving device.

16. The method of claim 9, wherein the signal of each of the plurality beams comprises data transmission and first pilot signal for pilot training,

the first pilot training of a first beam of the beam set and the first pilot training of a second beam of the plurality of beams are mutually orthogonal.

17. A signal transmitting electronic device, comprising:

at least one storage medium including a set of instructions for per-beam signal synchronization; and

at least one processor in communication with the at least one storage medium, wherein when executing the set of instructions, the processor is directed to conduct a wireless communication with a signal receiving device via beamforming, during which the at least one processor is directed to;

determine a beam set to send beam domain signals to the signal receiving device;

for a beam domain signal of each individual beam of the beam set,

individually synchronize the beam domain signal in each beam of the beam set; and

send the beam domain signal to the signal receiving device, wherein to individually synchronize the beam domain signal in each of the plurality of beams, the at least one processor is further directed to;

determine a target frequency adjustment based on frequency offset of the beam domain signal that will be induced when the beam domain signal is transmitted to the signal receiving device; and

adjust at least one frequency independent variable of the beam domain signal by the target frequency adjustment,

wherein the beam domain signal of each beam comprises a plurality of transmission blocks, and wherein to determine the target frequency adjustment, the processor is further directed to;

for each of the plurality of transmission blocks,

determine a candidate minimum frequency adjustment as a minimum frequency offset of the beam domain signal that will be induced to the beam;

determine a candidate maximum frequency adjustment as a maximum frequency offset of the beam domain signal that will be induced to the beam;

determine a lower bound value of the target frequency adjustment as the minimum of the plurality of the candidate minimum frequency adjustments;

determine an upper bound value of the target frequency adjustment as the maximum of the plurality of the candidate maximum frequency adjustments; and

select a value of the target frequency adjustment between the lower bound value and upper bound value.

18. The device of claim 17, wherein to individually synchronize the beam domain signal in each of the plurality of beams, the at least one processor is further directed to:

determine a target time adjustment based on time shift of the beam domain signal that will be induced when the beam domain signal is transmitted to the signal receiving device; and

adjust at least one time independent variable of the beam domain signal by the target time adjustment.

19. The device of claim 18,

wherein to determine the target time adjustment, the processor is further directed to:

for each of the plurality of transmission blocks, determine a candidate time adjustment as a minimum time shift of the beam domain signal that will be induced to the beam;

determine the target time adjustment as the minimum of the plurality of the candidate time adjustment values.

20. The device of claim 17, wherein each of the plurality of beams is a millimeter-wave beam or a Terahertz beam associated with a same predetermined frequency.

21. The device of claim 17, wherein the plurality of beams comprises a group of mutually non-overlapping beams.

22. The device of claim 17, wherein the wireless communication comprises a massive multiple-input multiple-output transmission.

23. The device of claim 17, wherein the signal of each beam of the beam set comprises data transmission and at least one first pilot signal for pilot training, and

the at least one first pilot signal is not mutually orthogonal with second pilot signals transmitted from the signal transmitting device to another signal receiving device.

24. The device of claim 17, wherein the signal of each of the plurality beams comprises data transmission and first pilot signal for pilot training,

the first pilot training of a first beam of the beam set and the first pilot training of a second beam of the plurality of beams are mutually orthogonal.

25. A method for per-beam signal synchronization comprising, during wireless communication between a signal transmitting device and a signal receiving device:

determine, by the signal transmitting device, a beam set to send beam domain signals to the signal receiving device;

for a beam domain signal of each individual beam of the beam set,

individually synchronizing, by the signal transmitting device, the beam domain signal in each beam of the beam set; and

sending, by the signal transmitting device, the beam domain signal to the signal receiving device, wherein the individually synchronizing of the beam domain signal in each of the plurality of beams further comprises;

determining a target frequency adjustment based on frequency offset of the beam domain signal that will be induced when the beam domain signal is transmitted to the signal receiving device; and

adjusting at least one frequency independent variable of the beam domain signal by the target frequency adjustment,

wherein the beam domain signal of each beam comprises a plurality of transmission blocks, and wherein the determining of the target frequency adjustment, the processor is further directed to;

for each of the plurality of transmission blocks,

determining a candidate minimum frequency adjustment as a minimum frequency offset of the beam domain signal that will be induced to the beam;

determining a candidate maximum frequency adjustment as a maximum frequency offset of the beam domain signal that will be induced to the beam;

determining a lower bound value of the target frequency adjustment as the minimum of the plurality of the candidate minimum frequency adjustments;

determining an upper bound value of the target frequency adjustment as the maximum of the plurality of the candidate maximum frequency adjustments; and

selecting a value of the target frequency adjustment between the lower bound value and upper bound value.

26. The method of claim 25, wherein the individually synchronizing of the beam domain signal in each of the plurality of beams further comprising:

determining a target time adjustment based on time shift of the beam domain signal that will be induced when the beam domain signal is transmitted to the signal receiving device; and

adjusting at least one time independent variable of the beam domain signal by the target time adjustment.

27. The method of claim 26,

wherein the determining of the target time adjustment further comprises:

for each of the plurality of transmission blocks, determining a candidate time adjustment as a minimum time shift of the beam domain signal that will be induced to the beam;

determining the target time adjustment as the minimum of the plurality of the candidate time adjustment values.

28. The method of claim 25, wherein each of the plurality of beams is a millimeter-wave beam or a Terahertz beam associated with a same predetermined frequency.

29. The method of claim 25, wherein the plurality of beams comprises a group of mutually non-overlapping beams.

30. The method of claim 25, wherein the wireless communication comprises a massive multiple-input multiple-output transmission.

31. The method of claim 25, wherein the signal of each beam of the beam set comprises data transmission and at least one first pilot signal for pilot training, and

the at least one first pilot signal is not mutually orthogonal with second pilot signals transmitted from the signal transmitting device to another signal receiving device.

32. The method of claim 25, wherein the signal of each beam of the beam set comprises data transmission and first pilot signal for pilot training,

the first pilot training of a first beam of the beam set and the first pilot training of a second beam of the plurality of beams are mutually orthogonal.

33. A beam division multiple access (BDMA) based massive multiple-input multiple-output (MIMO) downlink transmission method with per-beam time/frequency synchronization, comprising:

performing beamforming at both base stations and user terminals by dividing channels in space, wherein both the base stations and the user terminals are equipped with antenna arrays, and wherein the numbers of beams formed at the base stations and the user terminals are several or several dozens;

performing synchronization of transmission signals in BDMA over each beam individually in beam sets of the user terminals, wherein each user terminal estimates the time/frequency adjustment parameters of the signals over each beam individually based on the received synchronization signals sent from the base stations, wherein performing synchronization of the transmission signals in BDMA over each beam individually in the beam sets of the user terminals comprises, for a beam domain signal of each individual beam in the beam sets of the user terminals;

determining a target frequency adjustment based on frequency offset of the beam domain signal when the beam domain signal is transmitted to the user terminals; and

adjusting at least one frequency independent variable of the beam domain signal by the target frequency adjustment,

wherein the beam domain signal of each beam comprises a plurality of transmission blocks, and wherein the determining of the target frequency adjustment further comprises;

for each of the plurality of transmission blocks,

determining a candidate minimum frequency adjustment as a minimum frequency offset of the beam domain signal induced to the beam;

determining a candidate maximum frequency adjustment as a maximum frequency offset of the beam domain signal induced to the beam;

determining a lower bound value of the target frequency adjustment as the minimum of the plurality of the candidate minimum frequency adjustments;

determining an upper bound value of the target frequency adjustment as the maximum of the plurality of the candidate maximum frequency adjustments; and

selecting a value of the target frequency adjustment between the lower bound value and upper bound value;

at the user terminals, applying time/frequency synchronization to received signals based on the estimates of the time/frequency adjustment parameters over each receive beam individually;

at the base stations, performing beam and user scheduling to select user terminals that communicate with the base stations over the same time/frequency resources and the corresponding transmit beams for each user terminal based on beam domain channel statistics or partial information, wherein the base station beam sets assigned to different scheduled user terminals are mutually non-overlapping; and

from the base stations, transmitting the pilot signals and data signals over the assigned beams for each scheduled user terminal wherein each scheduled user terminal applies per-beam time/frequency synchronization to the received signal over the receive beams;

pilot signals are not required to be orthogonal for different user terminals,

wherein BDMA based massive MIMO downlink wireless transmission is dynamically adjusted when the statistics or partial information of the channels between the base stations and the user terminals vary.

34. A beam division multiple access (BDMA) based massive multiple-input multiple-output (MIMO) uplink transmission method with per-beam time/frequency synchronization, comprising:

performing beamforming at both base stations and user terminals by dividing channels in space, wherein both the base stations and the user terminals are equipped with antenna arrays, and wherein the numbers of beams formed at the base stations and the user terminals are several or several dozens;

performing synchronization of transmission signals in BDMA over each beam individually in beam sets of the user terminals, wherein each user terminal estimates the time/frequency adjustment parameters of the signals over each beam individually based on the received synchronization signals sent from the base stations, wherein performing synchronization of the transmission signals in BDMA over each beam individually in the beam sets of the user terminals comprises, for a beam domain signal of each individual beam in the beam sets of the user terminals;

determining a target frequency adjustment based on frequency offset of the beam domain signal when the beam domain signal is transmitted to the user terminals; and

adjusting at least one frequency independent variable of the beam domain signal by the target frequency adjustment,

wherein the beam domain signal of each beam comprises a plurality of transmission blocks, and wherein the determining of the target frequency adjustment further comprises;

for each of the plurality of transmission blocks,

determining a candidate minimum frequency adjustment as a minimum frequency offset of the beam domain signal induced to the beam;

determining a candidate maximum frequency adjustment as a maximum frequency offset of the beam domain signal induced to the beam;

determining a lower bound value of the target frequency adjustment as the minimum of the plurality of the candidate minimum frequency adjustments;

determining an upper bound value of the target frequency adjustment as the maximum of the plurality of the candidate maximum frequency adjustments; and

selecting a value of the target frequency adjustment between the lower bound value and upper bound value;

at the user terminals, applying time/frequency synchronization to the transmit signals based on the estimates of the time/frequency adjustment parameters over each transmit beam individually;

at the base stations, performing beam and user scheduling to select user terminals that communicate with the base stations over the same time/frequency resources and the corresponding receive beams for each user terminal based on beam domain channel statistics or partial information; and

at the selected user terminals, applying per-beam time/frequency synchronization to the transmit pilot and data signals over the transmit beams, wherein the base stations process the signals over the assigned receive beams, and wherein pilot signals sent from different user terminals are not required to be orthogonal,

wherein BDMA based massive MIMO uplink wireless transmission is dynamically adjusted when the statistics or partial information of the channels between the base stations and the user terminals vary.