CFI Signaling for Heterogeneous Networks with Multiple Component Carriers in LTE-Advanced
This invention mitigates interference in wireless telephony in heterogeneous networks having a macro base station and a low power base station. This invention attempts to avoid cross carrier scheduling on an anchor carrier and a non-anchor carrier. If cross carrier scheduling is unavoidable, then this invention attempts: (1) semi-statically signalling a CFI value on a cross-scheduled component carrier; (2) semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier setting a Physical Hybrid ARQ Indicator CHannel (PHICH) value to be maximum; or (3) semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier using Physical Control Format Indicator CHannel (PCFICH) power boosting on cross-scheduled component carriers (CC).
1 . A method of mitigating interference in wireless telephony when a first user equipment communicates with a first base station and a second user equipment communicates with a second base station having lower transmitter power than the first base station and an overlapping area of coverage with the first base station comprising the steps of:
determining whether the first user equipment is within or near the area of the second base station;
determining whether the second user equipment is receiving interference from the first base station; and
if the first user equipment is within or near the area of the second base station or if the second user equipment is receiving interference from the first base station, then prohibiting cross carrier scheduling for conveying Physical Downlink Control CHannel (PDCCH) information on an anchor carrier for the first and second user equipments receiving their Physical Downlink Shared CHannel (PDSCH) on a non-anchor carrier.
2 . The method of claim 1 , further comprising the step of:
if the first user equipment is within or near the area of the second base station or if the second user equipment is receiving interference from the first base station and cross carrier scheduling is not possible, then semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier to the user equipment experiencing poor geometry arising from unacceptable cross-tier interference.
3 . The method of claim 1 , further comprising the step of:
if the first user equipment is within or near the area of the second base station or if the second user equipment is receiving interference from the first base station and prohibiting cross carrier scheduling is not possible, then semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier for conveying Physical Downlink Control CHannel (PDCCH) information on an anchor carrier for the first and second user equipments receiving their Physical Downlink Shared CHannel (PDSCH) on a non-anchor carrier.
4 . The method of claim 1 , further comprising the step of:
if the first user equipment is within or near the area of the second base station or if the second user equipment is receiving interference from the first base station and prohibiting cross carrier scheduling is not possible, then semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier setting a Physical Hybrid ARQ Indicator CHannel (PHICH) value to be maximum Physical Downlink Control CHannel (PDCCH) control region duration on a Master Information Block (MIB).
5 . The method of claim 1 , further comprising the step of:
if the first user equipment is within or near the area of the second base station or if the second user equipment is receiving interference from the first base station and prohibiting cross carrier scheduling is not possible, then semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier using Physical Control Format Indicator CHannel (PCFICH) power boosting on cross-scheduled component carriers (CC).
6 . The method of claim 1 , further comprising the step of:
if the first user equipment is within or near the area of the second base station or if the second user equipment is receiving interference from the first base station and prohibiting cross carrier scheduling is not possible, then performing a selected one of (1) semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier for conveying Physical Downlink Control CHannel (PDCCH) information on an anchor carrier for the first and second user equipments receiving their Physical Downlink Shared CHannel (PDSCH) on a non-anchor carrier, (2) semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier setting a Physical Hybrid ARQ Indicator CHannel (PHICH) value to be maximum Physical Downlink Control CHannel (PDCCH) control region duration on a Master Information Block (MIB) or (3) semi-statically signalling a channel quality information (CSI) value on a cross-scheduled component carrier using Physical Control Format Indicator CHannel (PCFICH) power boosting on cross-scheduled component carriers (CC).