Terminal apparatus, base station apparatus, and communication system

Abstract

A terminal apparatus includes: a channel estimating unit that receives signals of pilot channels which are allocated to respective base station antennas and are orthogonal to each other and estimates channels with the respective base station antennas based on the signals of the pilot channels; an antenna selecting/phase amount calculating unit that performs selection of a base station antenna or calculation of phase rotation amounts of the base station antennas based on a result of channel estimation by the channel estimating unit; and a transmission unit that transmits an identification of the base station antenna selected by the antenna selecting/phase amount calculating unit or the phase rotation amounts calculated by the antenna selecting/phase amount calculating unit.

1 . A terminal apparatus comprising:
 a channel estimating unit that receives signals of pilot channels allocated to respective base station antennas and orthogonal to each other, and estimates channels with the respective base station antennas based on the signals of the pilot channels;   an antenna selecting/phase amount calculating unit that performs selection of a base station antenna or calculation of phase rotation amounts of the base station antennas, based on a result of channel estimation by the channel estimating unit; and   a transmission unit that transmits an identification of the base station antenna selected by the antenna selecting/phase amount calculating unit or the phase rotation amounts calculated by the antenna selecting/phase amount calculating unit.   
     
     
         2 . The terminal apparatus as recited in  claim 1 , further comprising a phase rotating unit that rotates the phase of the result of channel estimation by the channel estimating unit by a predetermined amount for the respective base station antennas,
 wherein the antenna selecting/phase amount calculating unit selects the base station antenna or calculates the phase rotation amounts of the base station antennas based on an output of the phase rotating unit.   
     
     
         3 . The terminal apparatus as recited in  claim 1 , wherein the channel estimating unit receives the pilot channels which are orthogonal to each other due to orthogonal codes allocated to the respective base station antennas, and performs channel estimation with the base station antennas based on the signals of the pilot channels. 
     
     
         4 . The terminal apparatus as recited in  claim 1 , wherein the antenna selecting/phase amount calculating unit selects a base station antenna to be subjected to phase rotation by a predetermined phase amount θ (0≦θ<2π) based on an output of the phase rotating unit, and
 the transmission unit transmits the identification of the base station antenna selected by the antenna selecting/phase amount calculating unit.   
     
     
         5 . The terminal apparatus as recited in  claim 4 , wherein the predetermined phase amount θ is π. 
     
     
         6 . The terminal apparatus as recited in  claim 1 , wherein the antenna selecting/phase amount calculating unit selects a base station antenna and calculates a phase rotation amount of the selected base station antenna, and
 the transmission unit transmits the identification of the base station antenna selected by the antenna selecting/phase amount calculating unit and the phase rotation amount calculated by the antenna selecting/phase amount calculating unit.   
     
     
         7 . The terminal apparatus as recited in  claim 1 , wherein the antenna selecting/phase amount calculating unit calculates the phase rotation amount or selects the antenna, based on an average value of outputs from the phase rotating unit for multiple subcarriers. 
     
     
         8 . A base station apparatus comprising:
 a transmission unit that transmits signals of pilot channels allocated to respective base station antennas and orthogonal to each other;   a transmission circuit controlling unit that directs a phase control for the respective base station antennas based on an identification of a base station antenna or a phase rotation amount included in a received signal; and   a phase rotating unit that applies phase rotation to respective subcarriers based on a direction from the transmission circuit controlling unit.   
     
     
         9 . The base station apparatus as recited in  claim 8 , wherein the transmission unit transmits the signals of the pilot channels orthogonal to each other due to orthogonal codes allocated to the respective base station antennas. 
     
     
         10 . The base station apparatus as recited in  claim 8 , wherein the phase rotating unit does not add phase rotation to subcarriers corresponding to the pilot channels, and adds to a subcarrier corresponding to a data signal both phase rotation in accordance with delay times added to the respective antennas and phase rotation based on the direction from the transmission circuit controlling unit. 
     
     
         11 . The base station apparatus as recited in  claim 8 , wherein the phase rotating unit adds phase rotation to subcarriers corresponding to the pilot channels based on the direction from the transmission circuit controlling unit, and adds to a subcarrier corresponding to a data signal both phase rotation in accordance with delay times added to the respective antennas, and phase rotation based on the direction from the transmission circuit controlling unit. 
     
     
         12 . The base station apparatus as recited in  claim 8 , wherein the phase rotating unit adds phase rotation to subcarriers corresponding to the pilot channels in accordance with delay times added to the respective antennas, and adds to a subcarrier corresponding to a data signal both phase rotation in accordance with a delay time added to the respective antennas, and phase rotation based on the direction from the transmission circuit controlling unit. 
     
     
         13 . The base station apparatus as recited in  claim 8 , wherein the received signal does not contain a phase rotation amount, and
 the transmission circuit controlling unit directs the phase rotation for the respective base station antennas based on the identification of the base station antenna included in the received signal, and a predetermined phase amount θ (0≦θ<2π) which is a value common to the respective subcarriers.   
     
     
         14 . The base station apparatus as recited in  claim 13 , wherein the predetermined phase amount θ is π. 
     
     
         15 . The base station apparatus as recited in  claim 8 , wherein delay times added to the respective base station antennas can be set to different values for terminal apparatuses communicating with the base station apparatus. 
     
     
         16 . A communication system comprising:
 the terminal apparatus as recited in  claim 1 ; and   the base station apparatus as recited in  claim 8  connected to the terminal apparatus by a wireless communication line.   
     
     
         17 . A communication system comprising:
 the terminal apparatus as recited in  claim 4 ; and   the base station apparatus as recited in  claim 13  connected to the terminal apparatus by a wireless communication line.   
     
     
         18 . A communication system comprising:
 the terminal apparatus as recited in  claim 5 ; and   the base station apparatus as recited in  claim 14  connected to the terminal apparatus by a wireless communication line.   
     
     
         19 . (canceled) 
     
     
         20 . A communication system comprising:
 a channel estimating unit that receives signals of pilot channels allocated to respective base station antennas and orthogonal to each other, and estimates channels with the respective base station antennas based on the signals of the pilot channels;   an antenna selecting/phase amount calculating unit that performs selection of a base station antenna or calculation of phase rotation amounts of the base station antennas, based on a result of channel estimation by the channel estimating unit;   a transmission unit that transmits an identification of the base station antenna selected by the antenna selecting/phase amount calculating unit or the phase rotation amounts calculated by the antenna selecting/phase amount calculating unit;   wherein the antenna selecting/phase amount calculating unit selects a base station antenna and calculates a phase rotation amount of the selected base station antenna, and the transmission unit transmits the identification of the base station antenna selected by the antenna selecting/phase amount calculating unit and the phase rotation amount calculated by the antenna selecting/phase amount calculating unit;   said system further including a base station apparatus comprising:   a transmission unit that transmits signals of pilot channels allocated to respective base station antennas and orthogonal to each other;   a transmission circuit controlling unit that directs a phase control for the respective base station antennas based on an identification of a base station antenna or a phase rotation amount included in a received signal; and   a phase rotating unit that applies phase rotation to respective subcarriers based on a direction from the transmission circuit controlling unit;   wherein the phase rotating unit does not add phase rotation to subcarriers corresponding to the pilot channels, and adds to a subcarrier corresponding to a data signal both phase rotation in accordance with delay times added to the respective antennas and phase rotation based on the direction from the transmission circuit controlling unit.   
     
     
         21 . A communication system comprising:
 a channel estimating unit that receives signals of pilot channels allocated to respective base station antennas and orthogonal to each other, and estimates channels with the respective base station antennas based on the signals of the pilot channels;   an antenna selecting/phase amount calculating unit that performs selection of a base station antenna or calculation of phase rotation amounts of the base station antennas, based on a result of channel estimation by the channel estimating unit;   a transmission unit that transmits an identification of the base station antenna selected by the antenna selecting/phase amount calculating unit or the phase rotation amounts calculated by the antenna selecting/phase amount calculating unit;   wherein the antenna selecting/phase amount calculating unit selects a base station antenna and calculates a phase rotation amount of the selected base station antenna, and the transmission unit transmits the identification of the base station antenna selected by the antenna selecting/phase amount calculating unit and the phase rotation amount calculated by the antenna selecting/phase amount calculating unit;   said system further including a base station apparatus comprising:   a transmission unit that transmits signals of pilot channels allocated to respective base station antennas and orthogonal to each other;   a transmission circuit controlling unit that directs a phase control for the respective base station antennas based on an identification of a base station antenna or a phase rotation amount included in a received signal; and   a phase rotating unit that applies phase rotation to respective subcarriers based on a direction from the transmission circuit controlling unit;   wherein the phase rotating unit adds phase rotation to subcarriers corresponding to the pilot channels based on the direction from the transmission circuit controlling unit, and adds to a subcarrier corresponding to a data signal both phase rotation in accordance with delay times added to the respective antennas, and phase rotation based on the direction from the transmission circuit controlling unit.