CHANNEL STATE INFORMATION FEEDBACK METHOD AND USER EQUIPMENT
A Channel State Information (CSI) feedback method and a User Equipment (UE) are disclosed. The method comprises the following steps of: determining a set of coordinated Base Stations (BSs) participating multi-BS coordination, the set of coordination BSs containing a serving BS and at least one non-serving BS; for each BS in the set of coordinated BSs: calculating a Signal to Interference and Noise Ratio (SINR) for a channel between a UE and the BS based on a hypothetical BS coordination mode corresponding to the BS; and deriving a Channel Quality Index (CQI) corresponding to the calculated SINR and feeding back the derived CQI to the serving BS.
1 . A Channel State Information (CSI) feedback method, comprising the following steps of:
determining a set of coordinated Base Stations (BSs) participating multi-BS coordination, the set of coordination BSs containing a serving BS and at least one non-serving BS;
for each BS in the set of coordinated BSs:
calculating a Signal to Interference and Noise Ratio (SINR) for a channel between a UE and the BS based on a hypothetical BS coordination mode corresponding to the BS; and
deriving a Channel Quality Index (CQI) corresponding to the calculated SINR and feeding back the derived CQI to the serving BS.
2 . The method according to claim 1 , wherein in the step of calculating SINR:
the hypothetical BS coordination mode corresponding to the serving BS in the set of coordinated BSs is a single BS transmission mode without coordination.
3 . The method according to claim 1 , wherein in the step of calculating SINR:
the hypothetical BS coordination mode corresponding to each non-serving BS in the set of coordinated BSs is one of a single BS transmission mode without coordination, a multi-BS joint transmission mode, a coordinated beamforming/coordinated scheduling mode and a dynamic cell selection mode.
4 . The method according to claim 3 , wherein in the step of calculating SINR:
an SINR for a non-serving BS is calculated in consideration of interferences from all other non-serving BSs in the set of coordinated BSs than the non-serving BS.
5 . The method according to claim 3 , wherein in the step of calculating SINR:
an SINR for a non-serving BS corresponding to the multi-BS joint transmission mode, the coordinated beamforming/coordinated scheduling mode or the dynamic cell selection mode is calculated in consideration of background interference and noise only.
6 . The method according to claim 3 , further comprising:
feeding back phase information associated with each non-serving BS corresponding to the multi-BS joint transmission mode to the serving BS.
7 . The method according to claim 1 , wherein the step of deriving CQI comprises:
deriving a CQI corresponding to the calculated SINR based on a mapping relationship between SINR and CQI.
8 . The method according to claim 7 , wherein the mapping relationship is obtained by shifting and extended filling a modulation and coding table in a Long Term Evolution (LTE) system.
9 . The method according to claim 7 , wherein the mapping relationship is obtained by selecting, at non-linear intervals, and extended filling a modulation and coding table in a Long Term Evolution (LTE) system.
10 . A User Equipment (UE), comprising:
a coordinated BS set determining unit configured for determining a set of coordinated Base Stations (BSs) participating multi-BS coordination, the set of coordination BSs containing a serving BS and at least one non-serving BS;
a Signal to Interference and Noise Ratio (SINR) calculating unit configured for calculating, for each BS in the set of coordinated BSs, an SINR for a channel between a UE and the BS based on a hypothetical BS coordination mode corresponding to the BS;
a Channel Quality Index (CQI) deriving unit configured for deriving, for each BS in the set of coordinated BSs, a CQI corresponding to the calculated SINR; and
a feedback unit configured for feeding back the derived CQI to the serving BS.
11 . The UE according to claim 10 , wherein the SINR calculating unit is configured for:
setting the hypothetical BS coordination mode corresponding to the serving BS in the set of coordinated BSs as a single BS transmission mode without coordination.
12 . The UE according to claim 10 , wherein the SINR calculating unit is configured for:
setting the hypothetical BS coordination mode corresponding to each non-serving BS in the set of coordinated BSs as one of a single BS transmission mode without coordination, a multi-BS joint transmission mode, a coordinated beamforming/coordinated scheduling mode and a dynamic cell selection mode.
13 . The UE according to claim 12 , wherein the SINR calculating unit is configured for:
calculating an SINR for a non-serving BS in consideration of interferences from all other non-serving BSs in the set of coordinated BSs than the non-serving BS.
14 . The UE according to claim 12 , wherein the SINR calculating unit is configured for:
calculating an SINR for a non-serving BS corresponding to the multi-BS joint transmission mode, the coordinated beamforming/coordinated scheduling mode or the dynamic cell selection mode in consideration of background interference and noise only.
15 . The UE according to claim 12 , the feedback unit is further configured for:
feeding back phase information associated with each non-serving BS corresponding to the multi-BS joint transmission mode to the serving BS.
16 . The UE according to claim 10 , wherein the CQI deriving unit is configured for:
deriving a CQI corresponding to the calculated SINR based on a mapping relationship between SINR and CQI.
17 . The UE according to claim 16 , wherein the CQI deriving unit is further configured for:
obtaining the mapping relationship by shifting and extended filling a modulation and coding table in a Long Term Evolution (LTE) system.
18 . The UE according to claim 16 , wherein the CQI deriving unit is further configured for:
obtaining the mapping relationship by selecting, at non-linear intervals, and extended filling a modulation and coding table in a Long Term Evolution (LTE) system.