1. An output driver comprising:
first means for receiving an input signal and in accordance therewith generating an output signal at a first output node;
second means for applying a variable current to said first output node; and
third means for controlling the magnitude of said variable current in accordance with said output signal;
wherein said third means includes a first circuit adapted to generate a first controlling current in accordance with said output signal, and
wherein said second means includes a first current mirror adapted to receive said first controlling current and output a scaled version of said first controlling current to said first output node.
2. The invention of claim 1 wherein said output driver is implemented differentially.
3. The invention of claim 2 wherein said first means includes an input circuit adapted to receive a first input signal and a second input signal and in accordance therewith output first and second output signals.
4. The invention of claim 3 wherein said input circuit includes a differential pair comprising transistors Q1 and Q2 adapted to receive said first and second input signals, respectively, and output said first and second output signals, respectively.
5. The invention of claim 4 wherein said differential pair is biased by a first current source I1.
6. The invention of claim 5 wherein said first means further includes an output circuit adapted to receive said first and second output signals from said input circuit and in accordance therewith generate third and fourth output signals at said first output node and a second output node, respectively.
7. The invention of claim 6 wherein said first circuit is adapted to receive said first and second output signals from said input circuit and in accordance therewith generate first and second controlling currents.
8. The invention of claim 7 wherein said second means further includes a second current mirror adapted to receive said second controlling current and output a scaled version of said second controlling current to said second output node.
9. The invention of claim 8 wherein said first controlling current is relatively large and said second controlling current is relatively small when said first input signal is more negative than said second input signal.
10. The invention of claim 9 wherein said first controlling current is relatively small and said second controlling current is relatively large when said first input signal is more positive than said second input signal.
11. The invention of claim 7 wherein said first circuit includes cascode transistors Q11 and Q12 coupled to said first and second output signals from said input circuit.
12. The invention of claim 11 wherein said cascode transistors Q11 and Q12 are biased by a second current source I2 and a third current source I3, respectively.
13. The invention of claim 12 wherein said current source I2 is slightly larger than I1.
14. The invention of claim 13 wherein said current source I3 is slightly larger than I1.
15. The invention of claim 12 wherein the emitter of Q11 is connected to the collector of Q1 through a resistor R1, and the emitter of Q12 is connected to the collector of Q2 through a resistor R2.
16. The invention of claim 15 wherein the collector of Q11 is coupled to said current source I2 and the collector of Q12 is coupled to said current source I3.
17. The invention of claim 16 wherein the collector of Q11 is also coupled to an input of said second current mirror, thereby supplying said second controlling current to said second current mirror.
18. The invention of claim 17 wherein the collector of Q12 is also coupled to an input of said first current mirror, thereby supplying said first controlling current to said first current mirror.
19. The invention of claim 12 wherein said first circuit further includes fourth means for providing a trickle current between said transistors Q11 and Q12.
20. The invention of claim 19 wherein said fourth means includes a resistor connected between the emitters of Q11 and Q12.
21. The invention of claim 20 wherein said current sources I2 and I3 both equal I1.
22. The invention of claim 6 wherein said output circuit includes a transistor Q13 adapted to receive said first output signal and in accordance therewith generate said third output signal at said first output node.
23. The invention of claim 6 wherein said output circuit includes a transistor Q14 adapted to receive said second output signal and in accordance therewith generate said fourth output signal at said second output node.
24. The invention of claim 6 wherein said output circuit includes a first Darlington pair adapted to receive said first output signal and in accordance therewith generate said third output signal at said first output node.
25. The invention of claim 6 wherein said output circuit includes a second Darlington pair adapted to receive said second output signal and generate said fourth output signal at said second output node.
26. The invention of claim 24 wherein said first current mirror is further adapted to generate a second scaled version of said first controlling current for biasing said first Darlington pair.
27. The invention of claim 25 wherein said second current mirror is further adapted to generate a second scaled version of said second controlling current for biasing said second Darlington pair.
28. An output driver comprising:
a first circuit for receiving an input signal and in accordance therewith generating an output signal at an output node;
a second circuit for generating a variable current in accordance with said output signal; and
a current mirror for generating a scaled version of said variable current and applying said scaled current to said output node.
29. A differential output driver comprising:
an input circuit for receiving first and second input signals and in accordance therewith generating first and second output signals;
an output circuit adapted to receive said first and second output signals and in accordance therewith generate third and fourth output signals at a first output node and a second output node, respectively;
a circuit adapted to receive said first and second output signals from said input circuit and in accordance therewith generate first and second controlling currents;
a first current mirror adapted to receive said first controlling current and apply a scaled version of said first controlling current to said first output node; and
a second current mirror adapted to receive said second controlling current and apply a scaled version of said second controlling current to said second output node.
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:
determining, by a served user equipment (UE), a downlink signal to noise ratio (SNIR) between the served UE and a serving base station;
computing an uplink transmit power level as a function of the downlink SNIR; and
transmitting uplink data, from the served UE, over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.
2. The method of claim 1, wherein computing an uplink transmit power level as a function of the downlink SNIR comprises:
determining the uplink transmit power level by summing a full power control (FPC) transmit power level, a product of a first adjustment factor (\u03b2) and the downlink SNIR, and a negative of a second adjustment factor (\u03942) when the product of the first adjustment factor (\u03b2) and the downlink SNIR is greater than or equal to the second adjustment factor (\u03942).
3. The method of claim 2, wherein the first adjustment factor (\u03b2) is provided to the serving UE by the serving base station.
4. The method of claim 2, wherein the second adjustment factor (\u03942) is provided to the serving UE by the serving base station.
5. The method of claim 2, wherein computing the uplink transmit power level in accordance with the downlink SNIR and the uplink power control algorithm further comprises:
setting the uplink transmit power level to a maximum power level when the product of a first adjustment factor (\u03b2) and the downlink SNIR is less than the second adjustment factor (\u03942).
6. The method of claim 1, wherein computing an uplink transmit power level as a function of the downlink SNIR comprises:
determining the uplink transmit power level in accordance with the following:
Ptx=P\u0192+max(0,\u03b2SINRDL\u2212\u03942),
where Ptx is the uplink transmit power level, P\u0192 is a full power control (FPC) transmit power level, \u03b2 is a first adjustment factor, SNIRDL is the downlink SNIR, and \u03942 is a second adjustment factor.
7. The method of claim 1, further comprising:
receiving, by the served UE, control signaling from the serving base station, wherein the control signaling specifies which parameters to use when computing the uplink transmit power level in accordance with the function of the downlink SNIR.
8. The method of claim 7, wherein the control signaling specifies at least one of an alpha parameter and a beta parameter for computing the uplink transmit power level in accordance with the function of the downlink SNIR.
9. A served user equipment (UE) comprising:
a processor; and
a computer readable storage medium storing programming for execution by the processor, the programming including instructions to:
determine a downlink signal to noise ratio (SNIR) between the served UE and a serving base station;
compute an uplink transmit power level as a function of the downlink SNIR; and
transmit uplink data over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.
10. A method comprising:
receiving, by a served UE, a message indicating target interference levels associated with neighboring base stations;
computing an uplink transmit power level as a function of the target interference levels associated with the neighboring base stations; and
transmitting uplink data, from the served UE, over the PUSCH resources in accordance with uplink transmit power level.
11. The method of claim 10, wherein computing the uplink transmit power level as a function of the target interference levels comprises:
determining path loss parameters between the served UE and each of the neighboring base stations; and
selecting, based on the path loss parameters, the uplink transmit power level such that interference experienced at the neighboring base stations as a result of the uplink transmission by the served UE does not exceed the target interference levels associated with the neighboring base stations.
12. A served user equipment (UE) comprising:
a processor; and
a computer readable storage medium storing programming for execution by the processor, the programming including instructions to:
receive a message indicating target interference levels associated with neighboring base stations;
compute an uplink transmit power level as a function of the target interference levels associated with the neighboring base stations; and
transmit uplink data over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.
13. A method comprising:
receiving, by a served user equipment (UE), a message indicating current interference levels associated with neighboring base stations;
computing, by the served UE, an uplink transmit power level as a function of the current interference levels associated with the neighboring base stations; and
transmitting uplink data from the served UE, over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.
14. The method of claim 13, wherein the message specifies which parameters to use when computing the uplink transmit power level in accordance with the function of the current interference levels associated with the neighboring base stations.
15. The method of claim 14, wherein the control signaling specifies at least one of an alpha parameter and a beta parameter for computing the uplink transmit power level in accordance with the function of the current interference levels associated with the neighboring base stations.
16. The method of claim 13, wherein computing an uplink transmit power level as a function of the current interference levels associated with the neighboring base stations comprises:
determining, by the served UE, interference ratios for the neighboring base stations, wherein a corresponding one of the interference ratios
(
q
i
\u03bb
i
)
for a given one of the neighboring base stations (BSi) comprises a ratio between an expected interference component (qi) attributable to the served UE experienced by the given neighboring base station and a current interference level (\u03bbi) for the given neighboring base station; and
computing, by the served UE, the power adjustment factor in accordance with the interference ratios for the serving base stations.
17. The method of claim 16, wherein computing the power adjustment factor in accordance with the interference ratios for the neighboring base stations comprises:
obtaining a delta-power parameter (\u03b4P) in accordance with the interference ratios for the neighboring base stations and a received signal power level (Sf) of the serving base station; and
computing the power adjustment factor as a function of the delta-power parameter (\u03b4P).
18. The method of claim 17, wherein obtaining the delta-power parameter (\u03b4P) in accordance with the interference ratios for the neighboring base stations and the received signal power level (Sf) of the serving base station comprises:
computing the delta-power parameter (\u03b4P) in accordance with the following:
\u03b4
\ue89e
\ue89e
P
=
S
f
–
10
\ue89e
log
(
\u2211
i
\ue89e
(
q
i
\u03bb
i
)
)
.
19. The method of claim 17, wherein computing the power adjustment factor as a function of the delta-power parameter (\u03b4P) comprises:
computing the power adjustment factor in accordance with the following:
\u0394P=\u03b2(\u03b4P)\u2212\u03942,
where \u03b2 is a first adjustment factor, and \u03942 is a second adjustment factor.
20. The method of claim 13, wherein computing the uplink transmit power level in accordance with the target interference levels associated with the neighboring base stations and the uplink power control algorithm comprises:
computing the uplink transmit power level in accordance with the following:
P
tx
=
P
f
+
\u03b2
(
S
f
–
10
\ue89e
log
(
\u2211
i
\ue89e
(
q
i
\u03bb
i
)
)
)
–
\u0394
\ue89e
\ue89e
2
,
where Ptx the uplink transmit power level, P\u0192 is a full power control (FPC) transmit power level, \u03b2 is a first adjustment factor, qi is an interference component attributable to the served UE experienced by a given one of the neighboring base stations, \u03bbi is a target interference power for the given base station, and \u03942 is a second adjustment factor.
21. A served user equipment (UE) comprising:
a processor; and
a computer readable storage medium storing programming for execution by the processor, the programming including instructions to:
receive a message indicating current interference levels associated with neighboring base stations;
compute an uplink transmit power level as a function of the current interference levels associated with the neighboring base stations; and
transmit uplink data over physical uplink shared channel (PUSCH) resources in accordance with uplink transmit power level.
22. A method comprising:
receiving, by a served user equipment (UE), an instruction from a serving base station, the instruction instructing the served UE to iteratively reduce an uplink transmit power level of the served UE until an interference level experienced by a neighboring base station has fallen below a threshold; and
iteratively reducing the uplink transmit power level of the served UE over a sequence of time intervals until an instruction to resume a normal power control procedure is received from the serving base station.
23. The method of claim 22, wherein iteratively reducing the transmit power level of the served UE over the sequence of time intervals until the instruction to resume the normal power control procedure is received from the serving base station comprises:
determining the uplink transmit power level by summing a full power control (FPC) transmit power level, a product of a first adjustment factor (\u03b2) and the downlink SNIR, and a negative of a second adjustment factor (\u03942); and
iteratively reducing the first adjustment factor (\u03b2) over the sequence of time intervals until the instruction to resume the normal power control procedure is received from the serving base station.