Mobility in a distributed antenna system

• US 8,787,186 B2
• Filed: 06/16/2011
• Issued: 07/22/2014
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Sexton, Thomas Aloysuis, Cliff, Charles Arthur, Pecen, Mark, Lusina, Paul James
• Primary Examiner(s): Wong, Warner
• Application Number:
  US13/161,706
• Publication Number:
  US 20120002564A1
• Time in Patent Office: 1,132 Days
• Field of Search: 370310-350
• US Class Current: 370/252
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
• CPC Class Codes: H04H 20/38 Arrangements for distribution where lower stations, e.g. receivers, interact with the broadcast
• CPC Class Codes: H04L 25/0232 by interpolation between sounding signals
• CPC Class Codes: H04L 25/0242 using matrix methods
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A device, method or system implements operations to receive compressed samples of wireless transmissions from a plurality of user equipment (UEs) traveling through different communication regions in a wireless network, and detect information in the wireless transmissions of the UEs based on the compressed samples.

Claims

1. A method comprising:

receiving samples of wireless transmissions from a plurality of user equipment (UEs) traveling through different communication regions in a wireless network, wherein the communication regions are pilot zones, and each pilot zone is assigned a corresponding set of pilots signals for use by UEs when traveling through the corresponding pilot zone, each of the wireless transmissions being based on an S-sparse set of vectors;

detecting information in the wireless transmissions of the UEs based on the samples;

constructing an overall matrix of estimated channels for the UEs, wherein the information in the wireless transmission of the UEs is detected based on at least the constructed matrix and the samples; and

estimating a channel for each of the UEs based on pilot signals employed by the UEs,

wherein two or more of the different communication regions are assigned the same set of pilot signals.

2. The method according to claim 1, further comprising:

identifying a presence of the UEs in the different communication regions at any given point in time; and

identifying communication parameters used by the UEs in the different communication regions.

3. The method according to claim 1, wherein the detecting information comprises implementing a linear program to solve a L1 minimization problem.

4. The method according to claim 1, wherein the detecting information operation comprises:

estimating a transmit vector for the wireless transmissions based on the samples and the estimated channels; and

demodulating the estimated transmit vector to obtain information in the wireless transmissions of the UEs.

5. The method according to claim 4, further comprising:

re-modulating the information to obtain a re-modulated transmit vector;

re-estimating channels for the UEs based on the re-modulated transmit vector;

estimating a transmit vector for a subsequent transmission period based on the samples and the re-estimated channels for the UEs; and

demodulating the estimated transmit vector to obtain information in the wireless transmissions of the UEs.

6. The method according to claim 1, wherein the detecting operation employs a linear program using a sparse representation matrix and a sensing matrix, and the matrices are selected to reduce at least a Candes Noise Coefficient.

7. The method according to claim 1, wherein the wireless network includes remote regional processors associated with respective communication regions, and the samples are received from the remote regional processors.

8. The method according to claim 7, wherein each of the remote regional processors allocates communication parameters for use by UEs in its respective communication region.

9. A method comprising:

receiving samples taken of a wireless transmission from user equipment (UE) traveling from a first pilot zone to a second pilot zone in a wireless network having a plurality of pilot zones, each pilot zone having an assigned set of pilot signal, the wireless transmission including a pilot signal selected from the set of pilot signals by the UE based on a scheduled assignment and being based on an S-sparse combination of a set of vectors;

identifying a presence of the UE in the second pilot zone;

identifying the selected pilot signal to be used by the UE in the second pilot zone based on the scheduled assignment; and

detecting information in the wireless transmission from the set of samples,

wherein the samples are sampled at different geographic locations in the second region at a given point in time, and

wherein the scheduled assignment is based on a system clock and a UE identifier (ID).

10. The method of claim 9, wherein the first and second zones are assigned a different set of pilot signals.

11. A communication system comprising:

a plurality of remote samplers {1, . . . , j, . . . , z} where z is a number of remote samplers, a j^th remote sampler capturing N samples during a word interval and transforming the N samples into M_j samples denoted collectively as y_j using a sensing matrix Φ

_j where M_j<

N/2 and M=M₁+ . . . +M_j+ . . . +M_z; and

a solver for receiving samples {y₁, . . . , y_j, . . . , y_z} from the remote samplers and formulating a soft estimate of a collection of data vectors {{tilde over (x)}₁, . . . , {tilde over (x)}_k, . . . , {tilde over (x)}_l} based on knowledge of transmission matrices {Ψ

₁, . . . , Ψ

_k, . . . , Ψ

_l} where l is a number of user equipment {1, . . . , k, . . . , l},

wherein a transmission matrix Ψ

_k is incoherent within a sensing matrix Ψ

_j for all pairs k, j according to a Restricted Isometry Property.

12. The system according to claim 11, wherein a quantized vector {circumflex over (x)}_k is associated with a soft vector {tilde over (x)}_k using a sparsity value s_k.

13. The system according to claim 12, further comprising a plurality of regional leaf brains for receiving samples from remote samplers in their respective regions, wherein a regional leaf brain from the plurality of regional leaf brains assigns a value s_k to a k^th user equipment.

14. The system according to claim 13, wherein the plurality of regional leaf brains includes a first regional leaf brain and a second regional leaf brain, the first regional leaf brain assigning a sparsity value s_k to a first user equipment, and the second regional leaf brain assigning a value s_k+1 to a second user equipment.

15. The system according to claim 13, wherein the plurality of regional leaf brains includes a first regional leaf brain and a second regional leaf brain, the first regional leaf brain assigning to a k^th user equipment a transmission matrix Ψ

_reuse and a second regional leaf brain assigning to a k+1^th user equipment the matrix Ψ

_reuse, wherein the solver is aware of the assignments and the solver estimates a complex path gain from the k^th user equipment to the j^th remote sampler.

16. The system according to claim 13, wherein the k^th user equipment uses a pilot matrix Ψ

_k in a given word interval at a time t_w where;

(1) the k^th user equipment determines the pilot matrix Ψ

_k by evaluating a formula using t_w or by reading a table using t_w, and

(2) a (k+l)^th user equipment determines a pilot matrix Ψ

_k+1 by evaluating a formula using t_w or by reading a table using t_w.

17. The system according to claim 16, wherein Ψ

_k+1 is identical to Ψ

_k at a time t=t_w.

18. The system according to claim 16, wherein during certain word intervals a set of transmission matrices Ψ

comprises pilot matrices and a k^th element x_k is a pattern with sparsity s_k=1 and x_k is known to the solver.

19. The system according to claim 18, wherein the set of transmission matrices Ψ

comprises columns of a Discrete Fourier Transform matrix.

20. The system according to claim 18, wherein the set of transmission matrices Ψ

comprises columns generated using a pseudo random number generator.

21. The system according to claim 11, wherein the solver creates a soft estimate {tilde over (x)} using a zero forcing method.

22. The system according to claim 11, wherein the solver creates a soft estimate using a maximum-likelihood method.

23. A method of operating user equipment comprising:

learning a number of uplink antennas passed per second; and

apportioning an uplink transmission bandwidth between data, signaling and pilot transmissions based on the learned number,

wherein a data transmission comprises s-sparse transmission based on a pseudo-random number-based transmission matrix Ψ

which is repopulated at certain time intervals.

24. A communication system comprising:

a plurality of remote samplers {1, . . . , j, . . . , z} where z is a number of remote samplers, a j^th remote sampler capturing N samples during a word interval and transforming the N samples into M_j samples denoted collectively as y_j using a sensing matrix Ψ

_j where M_j<

N/2 and M=M₁+ . . . +M_j+ . . . +M_z; and

a solver for receiving samples {y₁, . . . , y_j, . . . , y_z} from the remote samplers and formulating a soft estimate of a collection of data vectors {{tilde over (x)}₁, . . . , {tilde over (x)}_k, . . . , {tilde over (x)}_l} based on a knowledge of transmission matrices {Ψ

₁, . . . , Ψ

_k, . . . , Ψ

_l} where l is a number of user equipment {1, . . . , k, . . . , l},

wherein the remote samplers perform sampling of a sparse or non-sparse data transmission.

25. The communication system according to claim 24, wherein an entropy of a transmitted user constellation is either 16-bits or 32-bits.

26. The communication system according to claim 24, wherein the non-sparse data transmission includes a checksum.

27. The communication system according to claim 26, wherein the solver computes a checksum from data formulated from the received samples, and deletes blocks of data where a checksum fails.

28. A communication system comprising:

a plurality of remote samplers for receiving wireless signals transmitted by one or more user equipment using a transmission matrix from one or more transmission matrices, each of the remote samplers capturing N samples during a word interval and transforming the N samples into M samples, where M<

N/2, using a sensing matrix from one or more sensing matrices; and

a solver for receiving the M samples from each of the remote samplers and formulating a soft estimate of data vectors based on a knowledge of the transmission matrices used by each of the one or more user equipment,

wherein all pairs of a sensing matrix and transmission matrix satisfy a Restricted Isometry Property.