Power control arrangement for long term evolution time division duplex method and apparatus
View Patent ↗Embodiments of the present invention provide methods, systems and apparatuses for optimizing downlink path loss (PL) measurements in time division duplex (TDD) systems enabling fast power control targeting to decrease fading margin. In one embodiment, a method of power control in a long term evolution time division duplex (TDD) system is provided. The method includes controlling a length of a path loss measurement filter based on an allocation type. A width and frequency position of the path loss measurement filter is made dependent on the allocation type.
1. An apparatus comprising:
a measuring unit configured to measure attenuation from a plurality of sub-bands of a frequency spectrum in which a physical uplink control channel is being transmitted; and
a calculating unit configured to calculate a path loss measurement as an average of the measurement of said attenuation from each of the plurality of sub-bands of the frequency spectrum,
wherein power control for said physical uplink control channel is calculated using the following formula:
P =min( P max ,10 log 10( M )+ P o +αPL+Δ mcs +f (Δ j )),
where P max is a maximum allowed user equipment power, M is a number of assigned resource blocks, α is a path loss compensation factor, P o is a cell and user equipment specific scaling parameter, PL is the downlink path loss measured at the user equipment, Δ mcs is MCS specific value, and f(Δ i ) is a user equipment specific closed loop correction value.
2. The apparatus of claim 1 , wherein said apparatus comprises a controller in a long term evolution time division duplex system.
3. The apparatus of claim 1 , wherein said path loss measurement is calculated using the following formula:
PL =( P 1 +P 2 + . . . +PN )/ N,
where PL is the path loss, and P1, P2, . . . PN are instantaneous channel attenuation measurements from the plurality of sub-bands.
4. The apparatus of claim 1 , wherein a combined channel attenuation is calculated using the following formula:
P
t
=
P
r
1
+
P
r
2
2
where P t is the combined channel attenuation between a user equipment antenna used for transmission in an uplink and two eNodeB antenna used for reception in the uplink, and P r1 and P r2 are the measured channel attenuation from two paths.
5. An apparatus comprising:
measuring means for measuring attenuation from a plurality of sub-bands of a frequency spectrum in which a physical uplink control channel is being transmitted; and
calculating means for calculating a path loss measurement as an average of the measurement of said attenuation from each of the plurality of sub-bands of the frequency spectrum,
wherein power control for said physical uplink control channel is calculated using the following formula:
P =min( P max ,10 log 10( M )+ P o +αPL+Δ mcs +f (Δ i )),
where P max is a maximum allowed user equipment power, M is a number of assigned resource blocks, α is a path loss compensation factor, P o is a cell and user equipment specific scaling parameter, PL is the downlink path loss measured at the user equipment, Δ mcs is MCS specific value, and f(Δ i ) is a user equipment specific closed loop correction value.
6. The apparatus of claim 5 , wherein said apparatus comprises a controller in a long term evolution time division duplex system.
7. The apparatus of claim 5 , wherein said path loss measurement is calculated using the following formula:
PL =( P 1 +P 2 + . . . +PN )/ N,
where PL is the path loss, and P1, P2, . . . PN are instantaneous channel attenuation measurements from the plurality of sub-bands.
8. The apparatus of claim 5 , wherein a combined channel attenuation is calculated using the following formula:
P
t
=
P
r
1
+
P
r
2
2
where P1 is the combined channel attenuation between a user equipment antenna used for transmission in an uplink and two eNodeB antenna used for reception in the uplink, and Pr1 and Pr2 are the measured channel attenuation from two paths.