1. A wind turbine comprising:
a nacelle;
a blade rotor hub adjacent to said nacelle;
a main shaft coupled to said hub and said nacelle;
a generator coupled to said main shaft between said nacelle and said hub, said generator having a housing containing a generator rotor adjacent to said main shaft and a stator positioned adjacent to and radially outward from said generator rotor;
a cylindrical roller bearing coupled between said main shaft and said housing adjacent to said nacelle; and,
a second bearing coupled between said main shaft and said housing adjacent to said hub, wherein said second bearing is spaced apart from said cylindrical roller bearing a distance equal to the diameter of said main shaft.
2. The wind turbine of claim 1 wherein said second bearing is a double-tapered roller bearing.
3. The wind turbine of claim 2 wherein said second bearing is a crossed roller bearing.
4. The wind turbine of claim 1 wherein said second bearing is a three row roller bearing.
5. A wind turbine comprising:
a tower;
a nacelle mounted for rotation at one end of said tower;
a blade rotor hub adjacent to said nacelle;
a main shaft coupled to said hub and said nacelle;
a direct drive generator coupled to a main shaft, said direct drive generator having a housing positioned between said nacelle and said blade rotor hub;
a first bearing coupled to said main shaft, said first bearing being positioned between said housing and said nacelle; and,
a second bearing coupled to said main shaft, said second bearing being positioned between said housing and said hub, whereby the distance between said first and second bearing is equal to the diameter of said main shaft.
6. The wind turbine of claim 5 wherein said first bearing is a cylindrical roller bearing.
7. The wind turbine of claim 6 wherein the second bearing is a cylindrical roller bearing.
8. The wind turbine of claim 6 wherein the second bearing is a tapered roller bearing.
9. A wind turbine comprising:
a tower;
a nacelle mounted for rotation at one end of said tower;
a blade rotor hub adjacent to said nacelle; a plurality of blades coupled to said hub a main shaft attached to said hub and mounted for rotation to said nacelle;
an electrical generator coupled to a main shaft, said direct drive generator having a stationary housing mounted to said nacelle; a first rotational support means for coupling said main shaft to said housing, said first rotational support means being positioned adjacent said nacelle; and,
a second rotational support means for coupling to said main shaft to said housing, said second rotational support means being positioned between said housing and said hub and spaced apart from said first rotational support means a distance equal to the diameter of said main shaft.
10. The wind turbine of claim 9 wherein said first rotational support means is a bearing.
11. The wind turbine of claim 10 wherein said second rotational support means is a bearing.
12. The wind turbine of claim 11 wherein said first bearing and said second bearing are cylindrical roller bearings.
13. The wind turbine of claim 11 wherein said first bearing is a cylindrical bearing and said second bearing is a double tapered roller bearing.
14. The wind turbine of claim 11 wherein said first bearing is a cylindrical bearing and said second bearing is a crossed roller bearing.
15. The wind turbine of claim 11 wherein said first bearing is a cylindrical bearing and said second bearing is a three row type roller bearing.
16. The wind turbine of claim 11 wherein said generator further comprises: a rotor coupled to said shaft, said rotor having coils for generating a magnetic field; and, a stator mounted within said housing, said stator having means for inducing electrical current in response to the movement of said magnetic field.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method comprising:
receiving a beam signal at a receiver of a communications system;
receiving an antenna signal at the receiver; and
estimating parameters of the received beam signal based on information received in the received antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the estimating of the parameters is further based on the received beam signal, and
wherein the antenna signal includes a common pilot channel, and estimating the parameters is based on signals received in the common pilot channel,
wherein the communication system is a cellular communication system and said cellular communication system comprising a plurality of cells, each cell comprising at least one sector,
wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over a part of a sector,
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor, and
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal.
2. A method comprising:
receiving a beam signal at a receiver of a communication system, the receiver having an adaptive antenna transmitter, wherein the communication system is a cellular system comprising a plurality of cells, each cell comprising at least one sector;
receiving an antenna signal at the receiver; and
estimating parameters of the received beam signal based on information received in the received antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimating of the parameters is further based on the received beam signal wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor.
3. A method comprising:
receiving a beam signal at a receiver of a communication system, the receiver having an adaptive antenna transmitter, wherein the communication system is a cellular system comprising a plurality of cells, each cell comprising at least one sector;
receiving an antenna signal at the receiver; and
estimating parameters of the received beam signal based on information received in the received antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimating of the parameters is further based on the received beam signal wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal;
wherein the expectation value of the time variant correlation coefficient, \u03c1, is calculated as
\u03c1
_
=
E
\u2061
conj
\u2061
(
h
^
P
–
CPICH
)
\xb7
h
^
DL
–
DPCCH
\uf603
h
^
P
–
CPICH
\uf604
\xb7
\uf603
h
^
DL
–
DPCCH
\uf604
,
wherein conj (\xb7) is the complex conjugation of the argument.
4. A method comprising:
receiving a beam signal having a dedicated channel at a receiver, the receiver having an adaptive antenna transmitter, wherein the communication system is a cellular system comprising a plurality of cells, each cell comprising at least one sector;
receiving an antenna signal at a receiver, the antenna signal having a primary common pilot channel; and
performing channel estimation on the received beam signal based on pilot signals received in the primary common pilot channel,
wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the channel estimation is additionally based on dedicated signals received in the dedicated physical channel wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor.
5. A method comprising:
receiving a beam signal having a dedicated channel at a receiver, the receiver having an adaptive antenna transmitter, wherein the communication system is a cellular system comprising a plurality of cells, each cell comprising at least one sector;
receiving an antenna signal at the receiver, the antenna signal having a primary common pilot channel; and
performing channel estimation on the received beam signal based on pilot signals received in the primary common pilot channel,
wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the channel estimation is additionally based on dedicated signals received in the dedicated physical channel wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal.
6. A method comprising:
receiving a beam signal having a dedicated channel at a receiver, the receiver having an adaptive antenna transmitter, wherein the communication system is a cellular system comprising a plurality of cells, each cell comprising at least one sector;
receiving an antenna signal at the receiver, the antenna signal having a primary common pilot channel; and
performing channel estimation on the received beam signal based on pilot signals received in the primary common pilot channel,
wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the channel estimation is additionally based on dedicated signals received in the dedicated physical channel wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal;
wherein the expectation value of the time variant correlation coefficient, \u03c1, is calculated as
\u03c1
_
=
E
\u2061
conj
\u2061
(
h
^
P
–
CPICH
)
\xb7
h
^
DL
–
DPCCH
\uf603
h
^
P
–
CPICH
\uf604
\xb7
\uf603
h
^
DL
–
DPCCH
\uf604
,
wherein conj (\xb7) is the complex conjugation of the argument.
7. An apparatus comprising:
a first input element configured to receive a beam signal;
a second input element configured to receive an antenna signal; and
an estimator, connected to the second input element, configured to estimate parameters of the received beam signal based on information received in the antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted in a communications system, the communications system comprising a plurality of cells and each cell comprising at least one sector and the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimator is further connected to the first input element, and configured to estimate the channel based on information additionally received in the beam signal;
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor.
8. An apparatus comprising:
a first input element configured to receive a beam signal;
a second input element configured to receive an antenna signal; and
an estimator, connected to the second input element, configured to estimate parameters of the received beam signal based on information received in the antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted in a communications system, the communications system comprising a plurality of cells and each cell comprising at least one sector and the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimator is further connected to the first input element, and configured to estimate the channel based on information additionally received in the beam signal;
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal.
9. An apparatus comprising:
a first input element configured to receive a beam signal;
a second input element configured to receive an antenna signal; and
an estimator, connected to the second input element, configured to estimate parameters of the received beam signal based on information received in the antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted in a communications system, the communications system comprising a plurality of cells and each cell comprising at least one sector and the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimator is further connected to the first input element, and configured to estimate the channel based on information additionally received in the beam signal;
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal;
wherein the exoectation value of the time variant correlation coefficient, \u03c1, is calculated as
\u03c1
_
=
E
\u2061
conj
\u2061
(
h
^
P
–
CPICH
)
\xb7
h
^
DL
–
DPCCH
\uf603
h
^
P
–
CPICH
\uf604
\xb7
\uf603
h
^
DL
–
DPCCH
\uf604
,
wherein conj (\xb7) is the complex conjugation of the argument.
10. An apparatus comprising:
first input means for receiving a beam signal;
second input means for receiving an antenna signal; and
estimating means, connected to the second input means, for estimating parameters of the received beam signal based on information received in the antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted in a communications system, the communications system comprising a plurality of cells and each cell comprising at least one sector and the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimating means is further connected to the first input means, for estimating the channel based on information additionally received in the beam signal;
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor.
11. An apparatus, comprising:
first input means for receiving a beam signal;
second input means for receiving an antenna signal; and
estimating means, connected to the second input means, for estimating parameters of the received beam signal based on information received in the antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted in a communications system, the communications system comprising a plurality of cells and each cell comprising at least one sector and the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimating means is further connected to the first input means, for estimating the channel based on information additionally received in the beam signal;
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal.
12. An apparatus comprising:
first input means for receiving a beam signal;
second input means for receiving an antenna signal; and
estimating means, connected to the second input means, for estimating parameters of the received beam signal based on information received in the antenna signal,
wherein estimating the parameters includes channel estimation,
wherein the antenna signal is transmitted in a communications system, the communications system comprising a plurality of cells and each cell comprising at least one sector and the antenna signal is transmitted over an entire sector and the beam signal is transmitted over part of a sector and the estimating means is further connected to the first input means, for estimating the channel based on information additionally received in the beam signal;
wherein the channel is estimated as:
\u0125joint={circumflex over (\u03b2)}\u0125DL-DPCCH+(1\u2212{circumflex over (\u03b2)})\u0125P-CPICH
wherein \u0125P-CPICH is a channel estimate obtained from the antenna signal and \u0125DL-DPCCH is a channel estimate obtained from the beam signal, and {circumflex over (\u03b2)} is a weight factor;
wherein the weight factor is calculated as:
\u03b2
^
=
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
(
1
–
\u03c1
_
)
\xb7
SNR
^
h
DL
–
DPCCH
+
\u03c1
_
\u2062
SNR
^
h
P
–
CPICH
,
where \u03c1 is the expectation value of the time variant correlation coefficient and S {circumflex over (N)} R is the estimate of the signal-to-noise-ratio of the signal;
wherein the expectation value of the time variant correlation coefficient, \u03c1, is calculated as
\u03c1
_
=
E
\u2061
conj
\u2061
(
h
^
P
–
CPICH
)
\xb7
h
^
DL
–
DPCCH
\uf603
h
^
P
–
CPICH
\uf604
\xb7
\uf603
h
^
DL
–
DPCCH
\uf604
,
wherein conj (\xb7) is the complex conjugation of the argument.