Method and device for adaptive antenna combining weights

US 6,362,781 B1
Filed: 06/30/2000
Issued: 03/26/2002
Est. Priority Date: 06/30/2000
Status: Expired due to Fees

First Claim

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1. A method of operating a communication system including at least one receiver comprising:

providing to the receiver a plurality of time-domain Doppler channel estimates for at least one transmitter, a plurality of Doppler sinusoids, and a spatial covariance matrix of a corrupting environment;

determining a Doppler spatial covariance matrix as a function of the time-domain Doppler channel estimates and the Doppler sinusoids;

determining a total Doppler spatial covariance matrix as a function of the spatial covariance matrix of the corrupting environment and the Doppler spatial covariance matrix;

determining a Doppler steering vector for at least one transmitter as a function of the Doppler channel estimates and the Doppler sinusoids; and

determining a combining weight for the at least one transmitter as a function of the total Doppler spatial covariance matrix and the Doppler steering vector for at least one transmitter.

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Abstract

A receiving device and method for operating a communication system are provided. The receiving device receives a plurality of time-domain Doppler channel estimates for at least one transmitter, a plurality of Doppler sinusoids, and a spatial covariance matrix of a corrupting environment. A Doppler spatial covariance matrix is created as a function of the time-domain Doppler channel estimates and the Doppler sinusoids. A total Doppler spatial covariance matrix is created as a function of the spatial covariance matrix of the corrupting environment and the Doppler spatial covariance matrix. A Doppler steering vector is created for at least one transmitter as a function of the Doppler channel estimates and the Doppler sinusoids. A combining weight for the at least one transmitter is then created as a function of the total Doppler spatial covariance matrix and the Doppler steering vector for at least one transmitter.

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33 Claims

1. A method of operating a communication system including at least one receiver comprising:
- providing to the receiver a plurality of time-domain Doppler channel estimates for at least one transmitter, a plurality of Doppler sinusoids, and a spatial covariance matrix of a corrupting environment;
  
  determining a Doppler spatial covariance matrix as a function of the time-domain Doppler channel estimates and the Doppler sinusoids;
  
  determining a total Doppler spatial covariance matrix as a function of the spatial covariance matrix of the corrupting environment and the Doppler spatial covariance matrix;
  
  determining a Doppler steering vector for at least one transmitter as a function of the Doppler channel estimates and the Doppler sinusoids; and
  
  determining a combining weight for the at least one transmitter as a function of the total Doppler spatial covariance matrix and the Doppler steering vector for at least one transmitter.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- - 2. The method of claim 1 wherein the Doppler spatial covariance matrix R for at least one receiver is computed according to:
    - $R (k, b) = \frac{1}{N} \sum_{u = 1}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} e^{j2π (v - w) n_{b} / N_{k}} \sum_{f = 0}^{K - 1} Q_{v} ({(k - f)}_{N}) Q_{w}^{*} ({(k - f)}_{N}) G_{u, v} (f) G_{u, w}^{*} (f)$
3. The method of claim 1 wherein the Doppler spatial covariance matrix R for at least one receiver is computed according to:
- $R (k) = \frac{1}{N} \sum_{b = 1}^{B} \sum_{u = 1}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} \begin{matrix} e^{j2π (v - w) n_{b} / N_{k}} \sum_{f = 0}^{K - 1} Q_{v} ({(k - f)}_{N}) Q_{w}^{*} ({(k - f)}_{N}) G_{u, v} (f) G_{u, w}^{*} (f \end{matrix}$ wherein $Q_{v} (k) = \frac{1}{\sqrt{N}} \sum_{n = 0}^{N - 1} q_{v} (n) e^{- j2π kl / N}, G_{u, v} (k) = \sum_{l = 0}^{L - 1} g_{u, v} (l) e^{- j2π kl / N},$ g_u,v(l)=h_u,v(l)e^{−
  
  j2π
  
  vn/N}^_k, and q_v(n)=e^j2π
  
  vn/N^_k. h_u,v(l) are the time-domain Doppler channels for user u, and q_v(n) are the Doppler sinusoids.
4. The method of claim 1 wherein the total Doppler spatial covariance matrix R_Tfor at least one receiver is computed according to:
- R_T(k,b)=R(k,b)+R_c(k,b).
5. The method of claim 1 wherein the total Doppler spatial covariance matrix R_Tfor at least one receiver is computed according to:
- R_T(k)=R(k)+R_c(k).
6. The method of claim 1 wherein the Doppler steering vector p for at least one receiver is computed according to:
- $p_{u} (k, b) = \frac{1}{\sqrt{N}} \sum_{v = - V}^{V} e^{j2π {vn}_{b} / N_{k}} Q_{v} (0) G_{u, v} (k) .$
7. The method of claim 1 wherein the Doppler steering vector p for at least one receiver is computed according to:
- $p_{u} (k) = \frac{1}{\sqrt{N}} \sum_{b = 1}^{B} \sum_{v = - V}^{V} e^{j2π {vn}_{b} / N_{k}} Q_{v} (0) G_{u, v} (k) .$
8. The method of claim 1 wherein the combining weight for at least one receiver is computed according to:
- w_u(k,b)=(R_T(k,b))^−
  
  1p_u(k,b)).

9. A method of operating a communication system including at least one receiver comprising:
- providing to the receiver a plurality of time-domain Doppler channel estimates for at least one transmitter, a plurality of Doppler signal correlation function, and a spatial covariance matrix of a corrupting environment;
  
  determining a Doppler spatial covariance matrix as a function of the time-domain Doppler channel estimates and the Doppler signal correlation function;
  
  determining a total Doppler spatial covariance matrix as a sum of the spatial covariance matrix of the corrupting environment and the Doppler spatial covariance matrix;
  
  determining a Doppler steering vector for at least one transmitter and at least one Doppler channel as a function of the Doppler channel estimates and the Doppler signal correlation function; and
  
  determining a combining weight for the at least one transmitter and at least one Doppler channel as a function of the total Doppler spatial covariance matrix and the Doppler steering vector for at least one transmitter and at least one Doppler channel.
- View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
- - 10. The method of claim 9 wherein the Doppler spatial covariance matrix R for communication systems with regular cyclic or no cyclic prefixes, and at least one receiver is computed according to:
    - $R (k, b) = \frac{1}{N} \sum_{u = - V}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} \begin{matrix} \begin{matrix} \begin{matrix} e^{j2π (v - w) n_{b} / N_{k}} \sum_{l = 0}^{L - 1} \sum_{t = 0}^{L - 1} h_{u, v} (l) h_{u, w}^{H} (t) R_{z} (v, w, l, t, k) \end{matrix} \end{matrix} \end{matrix},$
11. The method of claim 9 wherein the Doppler spatial covariance matrix R for communication systems with regular cyclic or no cyclic prefixes, and at least one receiver is computed according to:
- $R (k, b) = \frac{1}{N} \sum_{u = - V}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} \begin{matrix} \begin{matrix} \begin{matrix} e^{j2π (v - w) n_{b} / N_{k}} \sum_{l = 0}^{L - 1} \sum_{t = 0}^{L - 1} h_{u, v} (l) h_{u, w}^{H} (t) R_{z} (v, w, l, t, k) \end{matrix} \end{matrix} \end{matrix},$ wherein h_u,v(l) are the time-domain Doppler channels for user u and R_z(v,w,l,t,k) is the Doppler signal correlation function which is given for no cyclic prefixes as R_z(v,w,l,t,k)=e^{−
  
  j2π
  
  k(l−
  
  t)/N}e^{−
  
  j2π
  
  (v−
  
  w)l/N}^_kα
  
  (v−
  
  w), wherein $α (v) = \sum_{n = 0}^{N - 1} e^{j2π vn / N_{k}} .$
12. The method of claim 9 wherein the Doppler spatial covariance matrix R for communication systems with no cyclic prefixes, and at least one receiver is computed according to:
- $R (k, b) = \frac{1}{N} \sum_{u = 1}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} e^{j2π (v - w) n_{b} / N_{k}} α (v - w) G_{u, v, w} (k) H_{u, w}^{H} (k)$ wherein $α (v) = \sum_{n = 0}^{N - 1} e^{j2π vn / N_{k}}, G_{u, v, w} (k) = \sum_{l = 0}^{L - 1} h_{u, v} (l) e^{- j2π (v - w) l / N_{k}} e^{- j2π kl / N}, and H_{u, v} (k) = \sum_{l = 0}^{L - 1} h_{u, v} (l) e^{- j2π kl / N} .$
13. The method of claim 9 wherein the Doppler spatial covariance matrix R for communication systems with regular cyclic or no cyclic prefixes, and at least one receiver is computed according to:
- $R (k) = \frac{1}{N} \sum_{b = 1}^{B} \sum_{u = - V}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} \begin{matrix} \begin{matrix} \begin{matrix} e^{j2π (v - w) n_{b} / N_{k}} \sum_{l = 0}^{L - 1} \sum_{t = 0}^{L - 1} h_{u, v} (l) h_{u, w}^{H} (t) R_{z} (v, w, l, t, k) \end{matrix} \end{matrix} \end{matrix},$ wherein h_u,v(l) are the time-domain Doppler channels for user u and R_z(v,w,l,t,k) is the Doppler signal correlation function which is given for regular cyclic prefixes as $R_{z} (v, w, l, t, k) = e^{- j2π k (l - t) / N} \begin{matrix} [\begin{matrix} \sum_{n = \max (0, l - t)}^{\min (N - 1, N - 1 + l - t)} e^{j2π (v - w) (n - l) / N_{k}} + \\ \sum_{n = 0}^{l - t - 1} e^{j2π (v - w) (n - l) / N_{k}} e^{- j2π wN / N_{k}} + \\ \sum_{n = N + l - t}^{N - 1} e^{j2π (v - w) (n - l) / N_{k}} e^{j2π wN / N_{k}} \end{matrix}] \end{matrix} .$
14. The method of claim 9 wherein the Doppler spatial covariance matrix R for communication systems with regular cyclic prefixes or no cyclic prefixes, and at least one receiver is computed according to:
- $R (k) = \frac{1}{N} \sum_{b = 1}^{B} \sum_{u = - V}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} \begin{matrix} \begin{matrix} \begin{matrix} e^{j2π (v - w) n_{b} / N_{k}} \sum_{l = 0}^{L - 1} \sum_{t = 0}^{L - 1} h_{u, v} (l) h_{u, w}^{H} (t) R_{z} (v, w, l, t, k) \end{matrix} \end{matrix} \end{matrix},$ wherein h_u,v(l) are the time-domain Doppler channels for user u and R_z(v,w,l,t,k) is the Doppler signal correlation function which is given for no cyclic prefixes as R_z(v,w,l,t,k)=e^{−
  
  j2π
  
  k(l−
  
  t)/N}e^{−
  
  j2π
  
  (v−
  
  w)l/N}^_kα
  
  (v−
  
  w), wherein $α (v) = \sum_{n = 0}^{N - 1} e^{j2π vn / N_{k}} .$
15. The method of claim 9 wherein the Doppler spatial covariance matrix R for communication systems with no cyclic prefixes, and at least one receiver is computed according to:
- $R (k) = \frac{1}{N} \sum_{b = 1}^{B} \sum_{u = 1}^{U} \sum_{v = - V}^{V} \sum_{w = - V}^{V} e^{j2π (v - w) n_{b} / N_{k}} α (v - w) G_{u, v, w} (k) H_{u, w}^{H} (k)$ wherein $α (v) = \sum_{n = 0}^{N - 1} e^{j2π vn / N_{k}}, G_{u, v, w} (k) = \sum_{l = 0}^{L - 1} h_{u, v} (l) e^{- j2π (v - w) l / N_{k}} e^{- j2π kl / N}, and H_{u, v} (k) = \sum_{l = 0}^{L - 1} h_{u, v} (l) e^{- j2π kl / N} .$
16. The method of claim 9 wherein the total Doppler spatial covariance matrix R_Tfor communication systems with no cyclic prefixes, and at least one receiver is computed according to R_T(k,b)=R(k,b)+R_c(k,b).
17. The method of claim 9 wherein the total Doppler spatial covariance matrix R_Tfor communication systems with no cyclic prefixes, and at least one receiver is computed according to R_T(k)=R(k)+R_c(k).
18. The method of claim 9 wherein the Doppler steering vector for at least one transmitter and at least one Doppler channel, p for communication systems with regular cyclic prefixes or no cyclic prefixes and at least one receiver is computed according to:
- $p_{u, v} (k, b) = \frac{1}{\sqrt{N}} \sum_{w = - V}^{V} e^{j2π {wn}_{b} / N_{k}} \sum_{l = 0}^{L - 1} h_{u, w} (l) R_{z} (w, v, l, 0, k) .$
19. The method of claim 9 wherein the Doppler steering vector for at least one transmitter and at least one Doppler channel, p for communication systems with no cyclic prefixes and at least one receiver is computed according to:
- $p_{u, v} (k, b) = \frac{1}{\sqrt{N}} \sum_{w = - V}^{V} e^{j2π {wn}_{b} / N_{k}} G_{u, w, v} (k) α (w - v) .$
20. The method of claim 9 wherein the Doppler steering vector for at least one transmitter and at least one Doppler channel, p for communication systems with regular cyclic prefixes or no cyclic prefixes and at least one receiver is computed according to:
- $p_{u, v} (k, b) = \frac{1}{\sqrt{N}} \sum_{b = 1}^{B} \sum_{w = - V}^{V} e^{j2π {wn}_{b} / N_{k}} \sum_{l = 0}^{L - 1} h_{u, w} (l) R_{z} (w, v, l, 0, k) .$
21. The method of claim 9 wherein the Doppler steering vector for at least one transmitter and at least one Doppler channel, p for communication systems with no cyclic prefixes and at least one receiver is computed according to:
- $p_{u, v} (k) = \frac{1}{\sqrt{N}} \sum_{b = 1}^{B} \sum_{w = - V}^{V} e^{j2π {wn}_{b} / N_{k}} G_{u, w, v} (k) α (w - v) .$
22. The method of claim 9 wherein the combining weight for at least one receiver is computed according to:
- w_u,v(k,b)=(R_T(k,b))^−
  
  1p_u,v(k,b).

23. A method of operating a communication system including at least one receiver comprising:
- providing to the receiver a plurality of time-domain Doppler channel estimates for at least one transmitter, a set of known pilot symbols, and a plurality of Doppler sinusoids;
  
  receiving a frequency-domain pilot sequence;
  
  determining the time domain Doppler pilot sequence as a function of the known pilot symbols and the Doppler sinusoids;
  
  converting the time domain Doppler pilot sequence into a frequency-domain Doppler pilot sequence;
  
  determining an estimate of the signal contribution of each known transmitter as a function of the frequency domain Doppler pilot sequence and the Doppler channel estimate for the each known transmitter;
  
  determining an estimate of the total signal contribution as a function of the estimates of the signal contribution of each known transmitter;
  
  determining a signal for the corrupting environment as a function of the estimate of the total signal contribution and the received frequency domain pilot sequence;
  
  determining a spatial covariance matrix of the corrupting environment as a function of the signal for the corrupting environment.
- View Dependent Claims (24, 25, 26, 27, 28, 29)
- - 24. The method of claim 23 wherein the time domain Doppler pilot sequence for communication systems with no cyclic prefixes is computed according to:
25. The method of claim 23 wherein the time domain Doppler pilot sequence for communication systems with regular cyclic prefixes is computed according to:
26. The method of claim 23 wherein the estimate of the signal contribution of each known transmitter is computed according to:
- ${\hat{x}}_{u} (k, b) = \frac{1}{\sqrt{N}} \sum_{u = 1}^{U} \sum_{v = - V}^{V} e^{j2π {vn}_{b} / N_{k}} \sum_{l = 0}^{L - 1} h_{u, v} (l) Z_{u, v, l} (k, b),$ where the frequency-domain Doppler pilot sequence is given as;
  
  $Z_{u, v, l} (k, b) = \sum_{n = 0}^{N - 1} z_{u, v} (n - l, b) e^{- j2π kn / N} .$
27. The method of claim 23 wherein the estimate of the total signal contribution is computed according to:
- ${\hat{x}}_{T} (k, b) = \sum_{u = 1}^{U} {\hat{x}}_{u} (k, b) .$
28. The method of claim 23 wherein the signal for the corrupting environment is computed according to:
29. The method of claim 23 wherein the spatial covariance matrix of the corrupting environment is computed according to:

30. A computer readable medium storing a computer program comprising:
- computer readable program code for receiving a pilot sequence;
  
  computer readable program code for converting the received pilot sequence into at least one frequency domain pilot sequence;
  
  computer readable program code for providing a plurality of Doppler channel estimates from the frequency domain pilot sequence; and
  
  computer readable program code for determining a plurality of combining weights from channel estimates.
- View Dependent Claims (31, 32, 33)
- - 31. The program of claim 30 further comprising:
32. The program of claim 30 further comprising:
- computer readable program code for determining a Doppler spatial covariance matrix as a function of a time-domain Doppler channel estimate and a Doppler sinusoid.
33. The program of claim 30 further comprising:
- computer readable program code for determining combining weights as a function of a Doppler spatial covariance and a Doppler steering vector.

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Current Assignee
Motorola, Inc. (Motorola Solutions, Inc.)
Original Assignee
Motorola, Inc. (Motorola Solutions, Inc.)
Inventors
Vook, Frederick W., Thomas, Timothy A.
Primary Examiner(s)
PHAN, DAO LINDA

Application Number

US09/607,736
Time in Patent Office

634 Days
Field of Search

342/361, 342/367, 342/378, 342/383, 455/67.6, 455/205
US Class Current

342/383
CPC Class Codes

H04B 7/01 Reducing phase shift

H04B 7/0854 using error minimizing algo...

Method and device for adaptive antenna combining weights

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Method and device for adaptive antenna combining weights

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