US2006258294A1PendingUtilityA1
Mobile station speed estimation
Est. expiryFeb 14, 2022(expired)· nominal 20-yr term from priority
H04B 17/25H04B 7/01G01S 11/10
38
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
The Doppler spreads of the received signals in a MIMO, SIMO or MISO mobile communication system are estimated from the derivatives of the path transfer function envelopes for the received signals. The estimated Doppler spreads is used to estimate the speed of the mobile station.
Claims
exact text as granted — not AI-modified1 - 48 . (canceled)
49 . A method of estimating the Doppler spread of a radio signal, the method comprising:
receiving a radio signal; deriving values for a derivative of an envelope of a path transfer function for said radio signal; and computing an estimate of the Doppler spread of said radio signal from the derivative values.
50 . A method according to claim 49 , wherein said values for the derivative of said envelope are derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using a Finite Impulse Response (FIR) filter.
51 . A method according to claim 50 , wherein said envelope signal comprises a sequence of samples representing the path transfer function envelope.
52 . A method according to claim 49 , wherein the computing of said estimate of the Doppler spread comprises determining a variance of the derivative values.
53 . A method according to claim 52 , wherein the computing of said estimate of the Doppler spread comprises determining a value indicative of the received power of said radio signal.
54 . A method according to claim 53 , wherein the Doppler spread estimate is calculated by determining the square root of the result of dividing twice said variance by said value indicative of the received power of the radio signal.
55 . A method according to claim 49 , wherein the Doppler spread estimate is calculated in accordance with the formula:
Doppler
spread
α
2
b
^
2
b
^
0
where
b
^
2
=
1
N
∑
n
=
1
N
r
.
^
nT
2
-
(
1
N
∑
n
=
1
N
r
.
^
nT
)
2
and
b
^
0
=
1
2
N
∑
n
=
1
N
r
nT
2
where r is the magnitude of the radio signal.
56 . A method of estimating the speed of a mobile station in a wireless communication system, the method comprising:
receiving a radio signal; deriving values for a derivative of an envelope of a path transfer function for said radio signal; computing an estimate of the Doppler spread of said radio signal from the derivative values; and deriving a value for the speed of said mobile station from said Doppler spread estimate.
57 . A method according to claim 56 , wherein said values for the derivative of said envelope are derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using a Finite Impulse Response (FIR) filter.
58 . A method according to claim 57 , wherein said envelope signal comprises a sequence of samples representing the path transfer function envelope.
59 . A method according to claim 57 , wherein the computing of said estimate of the Doppler spread comprises determining a variance of the derivative values.
60 . A method according to claim 59 , wherein the computing of said estimate of the Doppler spread comprises determining a value indicative of the received power of said radio signal.
61 . A method according to claim 60 , wherein the Doppler spread estimate is calculated by determining the square root of the result of dividing twice said variance by said value indicative of the received power of the radio signal.
62 . A method according to claim 56 , wherein the Doppler spread estimate is cacluated in accordance with the formula:
Doppler
spread
α
2
b
^
2
b
^
0
where
b
^
2
=
1
N
∑
n
=
1
N
r
.
^
nT
2
-
(
1
N
∑
n
=
1
N
r
.
^
nT
)
2
and
b
^
0
=
1
2
N
∑
n
=
1
N
r
nT
2
where r is the magnitude of the radio signal.
63 . A method according to claim 56 , wherein the speed of the mobile station is calculated in accordance with the formula:
speed
α
f
d
spread
f
c
where f dspread is the Doppler spread and f c is the carrier frequency of said radio signal.
64 . A method of estimating the speed of a mobile station in a wireless communication system, the method comprising:
receiving a radio signal; deriving first and second values for a derivative of an envelope of said radio signal; computing first and second estimates of the Doppler spread of said radio signal from the derivative values; and deriving a value for the speed of said mobile station from said Doppler spread estimates.
65 . A method according to claim 64 , wherein said first value for the derivative of the envelope of said radio signal is derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using a Finite Impulse Response (FIR) filter and said second value for the derivative of the envelope of said radio signal is derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using an FIR filter, the first value being derived using a low-pass filter characteristic having a lower cut-off frequency than that of the low-pass filter characteristic used for deriving said second value.
66 . A method according to claim 65 , wherein the first value for the derivative of the envelope of said radio signal is further derived by downsampling the output of the low-pass filtering.
67 . A method according to claim 65 , wherein said envelope signal comprises a sequence of samples representing the path transfer function envelope.
68 . A method according to claim 65 , wherein the computing of said first and second estimates of the Doppler spread comprises determining variances of said first and second derivative values, respectively.
69 . A method according to claim 68 , wherein the computing of each of said estimates of the Doppler spread comprises determining a value indicative of the received power of said radio signal.
70 . A method according to claim 69 , wherein the first and second Doppler spread estimates are calculated by determining the square root of the result of dividing twice the respective variance by said value indicative of the received power of the radio signal.
71 . A method according to claim 64 , wherein the Doppler spread estimates are calculated in accordance with the formula:
Doppler
spread
α
2
b
^
2
b
^
0
where
b
^
2
=
1
N
∑
n
=
1
N
r
.
^
nT
2
-
(
1
N
∑
n
=
1
N
r
.
^
nT
)
2
and
b
^
0
=
1
2
N
∑
n
=
1
N
r
nT
2
where r is the magnitude of the radio signal.
72 . A method according to claim 64 , comprising deriving first and second speed estimates values from the first and second Doppler spreads, respectively, and selecting the first or second speed estimate value in dependence on the magnitude of the first or second speed estimate value to provide said speed estimate.
73 . A method according to claim 72 , wherein the first and second speed estimate values are calculated in accordance with the formula:
speed
α
f
d
spread
f
c
where f dspread is a Doppler spread and f c is the carrier frequency of said radio signal.
74 . A mobile station of a wireless communication network, the mobile station including radio receiver means for receiving a radio signal and outputting a baseband signal and processing means for processing said baseband signal, wherein the processing means is configured for estimating the Doppler spread of a radio signal by deriving values for a derivative of an envelope of a path transfer function for a radio signal, received by said radio receiver means, and computing an estimate of the Doppler spread of said radio signal from the derivative values.
75 . A mobile station according to claim 74 , wherein said processing means is configured such that said values for the derivative of said envelope are derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using a Finite Impulse Response (FIR) filter.
76 . A mobile station according to claim 75 , wherein the radio receiver means outputs said baseband signal as a plurality of samples.
77 . A mobile station according to claim 74 , wherein the processing means is configured such that the computing of said estimate of the Doppler spread comprises determining a variance of the derivative values.
78 . A mobile station according to claim 77 , wherein the processing means is configured such that the computing of said estimate of the Doppler spread comprises determining a value indicative of the received power of said radio signal.
79 . A mobile station according to claim 78 , wherein the processing means is configured such that the Doppler spread estimate is calculated by determining the square root of the result of dividing twice said variance by said value indicative of the received power of the radio signal.
80 . A mobile station according to claim 74 , wherein the processing means is configured such that the Doppler spread estimate is calculated in accordance with the formula:
Doppler
spread
α
2
b
^
2
b
^
0
where
b
^
2
=
1
N
∑
n
=
1
N
r
.
^
nT
2
-
(
1
N
∑
n
=
1
N
r
.
^
nT
)
2
and
b
^
0
=
1
2
N
∑
n
=
1
N
r
nT
2
where r is the magnitude of the radio signal.
81 . A mobile station of a wireless communication network, the mobile station including radio receiver means for receiving a radio signal and outputting a baseband signal and processing means for processing said baseband signal, wherein the processing means is configured for estimating the speed of the mobile station by deriving values for a derivative of a path transfer function envelope for a radio signal, received by said radio receiver means, computing an estimate of the Doppler spread of said radio signal from the derivative values and deriving a value for the speed of the mobile station from said Doppler spread estimate.
82 . A mobile station according to claim 81 , wherein said processing means is configured such that said values for the derivative of said envelope are derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using a Finite Impulse Response (FIR) filter.
83 . A mobile station according to claim 82 , wherein the radio receiver means outputs said baseband signal as a plurality of samples.
84 . A mobile station according to claim 81 , wherein the processing means is configured such that the computing of said estimate of the Doppler spread comprises determining a variance of the derivative values.
85 . A mobile station according to claim 84 , wherein the processing means is configured such that the computing of said estimate of the Doppler spread comprises determining a value indicative of the received power of said radio signal.
86 . A mobile station according to claim 85 , wherein the processing means is configured such that the Doppler spread estimate is calculated by determining the square root of the result of dividing twice said variance by said value indicative of the received power of the radio signal.
87 . A mobile station according to claim 81 , wherein the processing means is configured such that the Doppler spread estimate is calculated in accordance with the formula:
Doppler
spread
α
2
b
^
2
b
^
0
where
b
^
2
=
1
N
∑
n
=
1
N
r
.
^
nT
2
-
(
1
N
∑
n
=
1
N
r
.
^
nT
)
2
and
b
^
0
=
1
2
N
∑
n
=
1
N
r
nT
2
where r is the magnitude of the radio signal.
88 . A mobile station of a wireless communication network, the mobile station including radio receiver means for receiving a radio signal and outputting a baseband signal and processing means for processing said baseband signal, wherein the processing means is configured for estimating the speed of the mobile station by deriving first and second values for a derivative of an envelope of a path transfer function envelope of a radio signal, received by said radio receiver means, computing first and second estimates of the Doppler spread of said radio signal from the derivative values and deriving a value for the speed of said mobile station from said Doppler spread estimates.
89 . A mobile station according to claim 88 , wherein the processing means is configured such that said first value for the derivative of said envelope is derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using a Finite Impulse Response (FIR) filter and said second value for the derivative of said envelope is derived by low-pass filtering an envelope signal representing the path transfer function envelope to band limit the envelope signal and filtering the band-limited envelope signal using an FIR filter, the first value being derived using a low-pass filter characteristic having a lower cut-off frequency than that of the low-pass filter characteristic used for deriving said second value.
90 . A mobile station according to claim 89 , wherein the processing means is configured such that the first value for the derivative of the envelope of said radio signal is further derived by downsampling the output of the low-pass filtering.
91 . A mobile station according to claim 89 , wherein the radio receiver means outputs the baseband signal as a sequence of samples.
92 . A mobile station according to claim 89 , wherein the processing means is configured such that the computing of said first and second estimates of the Doppler spread comprises determining variances of said first and second derivative values, respectively.
93 . A mobile station according to claim 92 , wherein the processing means is configured such that the computing of each of said estimates of the Doppler spread comprises determining a value indicative of the received power of said radio signal.
94 . A mobile station according to claim 93 , wherein the processing means is configured such that the first and second Doppler spread estimates are calculated by determining the square root of the result of dividing twice the respective variance by said value indicative of the received power of the radio signal.
95 . A mobile station according to claim 88 , wherein the processing means is configured such that the Doppler spread estimates are calculated in accordance with the formula:
Doppler
spread
α
2
b
^
2
b
^
0
where
b
^
2
=
1
N
∑
n
=
1
N
r
.
^
nT
2
-
(
1
N
∑
n
=
1
N
r
.
^
nT
)
2
and
b
^
0
=
1
2
N
∑
n
=
1
N
r
nT
2
where r is the magnitude of the radio signal.
96 . A mobile station according to claim 88 , wherein the processing means is configured for deriving first and second speed estimate values from the first and second Doppler spreads, respectively, and selecting the first or second speed estimate value in dependence on the magnitude of the first or second speed estimate value to provide said speed estimate.
97 . A mobile station according to claim 96 , wherein the processing means is configured such that the first and second speed estimate values are calculated in accordance with the formula:
speed
α
f
d
spread
f
c
where f dspread is the Doppler spread and f c is the carrier frequency of said radio signal.Join the waitlist — get patent alerts
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