Channel state information feedback method and user equipment

Abstract

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.