Apparatus for controlling a plurality of receiver fingers in a CDMA receiver
View Patent ↗A method and apparatus controls a plurality of receiver channel elements ( 102 a– 102 n ), such as RAKE receiver fingers in a CDMA receiver, by assigning a real time priority metric to each channel type. For example, a receiver channel element management module ( 109 ) generates a channel weight value ( 216 ) and a receiver channel element factor value ( 218 ). The channel weight value ( 216 ) is dynamically determined on a per channel type basis representing an extent of energy demanded by a channel. For example, a channel at a higher rate may be programmed to start off with higher energy needs as compared to a different channel type, such as a voice channel which may communicate information at a lower rate. The receiver channel element factor value ( 218 ) is used to determine an impact of deassigning receiver fingers so that the dropped receiver finger is the one that is least harmful to all channels.
1. A method for controlling a plurality of receiver channel elements in a CDMA receiver, each receiver channel element configured to receive a plurality of different channel, comprising the steps of:
determining a channel weight value on a per channel type basis, representing an extent of energy demanded by a channel, based on at least a bench weight value and a current channel error value;
determining a suitable receiver channel element assignment based on the channel weight value;
determining a finger factor value, representing a performance valuation metric for a receiver channel element, based on the channel weight value;
determining a suitable receiver channel element deassignment based on the finger factor value; and
wherein the channel weight value is determined at least in part on the following formula:
Wc
=
(
Bench_wt
)
-
(
current_channel
_error
_value
)
Base_value
+
∑
all_fingers
energy_from
_allchannelsfor
_given
_channel
_type
where Base_value is a redefined scaling value.
2. The method of claim 1 wherein the step of determining a suitable receiver channel element deassignment includes de-assigning a receiver channel element based on the finger factor value by dropping a receiver channel element having a lowest finger factor value.
3. The method of claim 2 further includes the step of assigning a receiver channel element having a highest channel weight value to receive a multipath signal.
4. The method of claim 1 wherein the step of determining the finger factor value is determined based at least in part on the following formula:
Fingerfactor_value
=
∑
all_channels
(
energy_to
_one
_channel
)
(
thatchannel_Wc
)
∑
all_channels
Wc
.
5. The method of claim 1 including the step of generating a channel weight table containing the channel weight value for each of the plurality of channels.
6. A method for controlling a plurality of receiver channel elements in a CDMA receiver, each receiver channel element configured to receive a plurality of different channels, comprising the steps of:
determining a channel weight value on a per channel basis, representing an extent of energy demanded by a channel, based on at least a bench weight value and a current channel error value;
determining a suitable receiver channel element assignment based on the channel weight value;
determining a finger factor value, representing a performance valuation metric for a receiver channel element, based on the channel weight value;
determining a suitable receiver channel element deassignment based on the finger factor value;
generating a channel weight table containing the channel weight value for each of the plurality of channels;
generating and storing a receiver channel element factor table containing a receiver channel element factor value for each of the plurality of receiver channel elements, and
de-assigning at least one of the plurality of receiver channel elements based on the receiver channel element factor value by dropping a receiver channel element having a lowest finger factor value in the receiver channel element factor table.
7. A method for controlling a plurality of receiver channel elements in a CDMA receiver, each receiver channel element configured to receive a plurality of channels, comprising the steps of:
determining a channel weight value (Wc) on a per channel type basis, representing an extent of energy demanded by a channel, based on at least a bench weight value and a current channel error value such that:
Wc
=
(
Bench_wt
)
-
(
current_channel
_error
_value
)
Base_value
+
∑
all_fingers
energy_from
_allchannelsfor
_given
_channel
_type
where Base_value is a scaling factor;
determining a finger factor value, representing a performance valuation metric for a receiver channel element, based on the channel weight value, such that:
Fingerfactor_value
=
∑
all_channels
(
energy_to
_one
_channel
)
(
thatchannel_Wc
)
∑
all_channels
Wc
;
and
determining a suitable receiver channel element de-assignment based on the finger factor value by assigning a receiver channel element having a highest channel weight value to receive a multipath signal and de-assigning a receiver channel element based on the finger factor value by dropping a receiver channel element having a lowest finger factor value.
8. The method of claim 7 including the step of generating a channel weight table containing the channel weight value for each of the plurality of channels.
9. The method of claim 7 including the steps of:
generating and storing a receiver channel element factor table containing a receiver channel element factor value for each of the plurality of receiver channel elements, and
de-assigning at least one of the plurality of receiver channel elements based on the receiver channel element factor value by dropping a receiver channel element having a lowest finger factor value in the receiver channel element factor table.
10. A wireless receiver having a plurality of receiver channel elements operative to receive spread spectrum signals, at least two of the plurality of receiver channel elements assigned to a received signal of the spread spectrum signals and wherein the spread spectrum signal comprises a channel of a plurality of different channels, comprising:
a receiver channel element management module, operatively coupled to the at least two of the plurality of receiver channel elements and operative to determine a suitable receiver channel element de-assignment based on a finger factor value, including:
a channel weight value determinator operative to determine a channel weight value on a per channel basis, representing an extent of energy demanded by a channel, based on at least a bench weight value and a current channel error value;
a finger factor value determinator operative to determine the finger factor value, based on the channel weight value, representing a performance valuation metric for a receiver channel element, based on the channel weight value; and
wherein the channel weight value determinator determines the channel weight value based at least in part on the following formula:
Wc
=
(
Bench_wt
)
-
(
current_channel
_error
_value
)
Base_value
+
∑
all_fingers
energy_from
_allchannelsfor
_given
_channel
_type
where Base_value is a predefined scaling value.
11. The wireless receiver of claim 10 wherein the finger factor value determinator determines the finger factor value at least in part based on the following formula:
Fingerfactor_value
=
∑
all_channels
(
energy_to
_one
_channel
)
(
thatchannel_Wc
)
∑
all_channels
Wc
.
12. The wireless receiver of claim 10 wherein the receiver channel element management module de-assigns a receiver channel element based on the finger factor value by dropping a receiver channel element having a lowest finger factor value.
13. The wireless receiver of claim 12 wherein the receiver channel element management module assigns a receiver channel element having a highest channel weight value to receive a multipath signal.
14. The wireless receiver of claim 13 wherein the wireless receiver is in a mobile communication unit.
15. A wireless receiver having a plurality of receiver channel elements operative to receive spread spectrum signals, at least two of the plurality of receiver channel elements assigned to a received signal of the spread spectrum signals and wherein the spread spectrum signal comprises a channel of plurality of different channels, comprising:
a receiver channel element management module, operatively coupled to the at least two of the plurality of receiver channel elements and operative to determine a suitable receiver channel element de-assignment based on a finger factor value, including:
a channel weight value determinator operative to determine a channel weight value on a per channel type basis, representing an extent of energy demanded by a channel, based on at least a bench weight value and a current channel error value;
a finger factor value determinator operative to determine the finger factor value, based on the channel weight value, representing a performance valuation metric for a receiver channel element, based on the channel weight value; and
memory, operatively coupled to the receiver channel element management module, containing a channel weight table containing the channel weight value for each of the plurality of channel types and a receiver channel element factor table containing a receiver channel element factor value for each of the plurality of receiver channel elements.