Method and apparatus for providing optimal transmission and reception beams in beamforming system

Abstract

A method of providing an optimal transmission or reception (Tx/Rx) beam in a beamforming system. The method includes receiving a reference signal and selecting an optimal Tx/Rx beam that guarantees an optimal channel environment based on the received reference signal determining a possibility of occurrence of a Tx/Rx beam mismatch between the selected optimal Tx/Rx beam and a Tx/Rx beam used for transmitting information on the selected optimal Tx/Rx beam; and when there is the possibility of the occurrence of the Tx/Rx beam mismatch, performing at least one of widening a beam width of the Tx/Rx beam, increasing a number of Tx/Rx beams, reducing a period of a beam selection operation for selecting the optimal Tx/Rx beam, and reducing a transmission period of the reference signal. Other embodiments including a beamforming system are also disclosed.

What is claimed is: 
     
         1 . A method of providing an optimal transmission or reception (Tx/Rx) beam in a beamforming system, the method comprising:
 receiving a reference signal and a control signal;   selecting an optimal Tx/Rx beam that guarantees an optimal channel environment based on the received reference signal and control signal;   determining whether a Tx/Rx beam mismatch occurs between the selected optimal Tx/Rx beam and an Tx/Rx beam used for transmitting information related to the selected optimal Tx/Rx beam;   if the Tx/Rx beam mismatch occurs, selecting a new Tx/Rx beam based on pre-received Tx/Rx beam information; and   transmitting compensation information including at least one of information related to a user equipment (UE) and information related to the optimal Tx/Rx beam through the new Tx/Rx beam.   
     
     
         2 . The method of  claim 1 , wherein the determining whether the Tx/Rx beam mismatch occurs comprises:
 determining whether the optimal Tx/Rx beam has a capability equal to or larger than a first threshold;   if the optimal Tx/Rx beam has the capability equal to or larger than the first threshold, determining whether response messages of pre-transmitted control signals or data have been received more than a predetermined number of times or more; and   if the response messages have not been received more that the predetermined number of times or more, determining that the Tx/Rx beam mismatch occurs.   
     
     
         3 . The method of  claim 1 , wherein the determining whether the Tx/Rx beam mismatch occurs comprises:
 determining whether the optimal Tx/Rx beam has a capability equal to or larger than a first threshold;   if the optimal Tx/Rx beam has the capability equal to or larger than the first threshold, determining whether channel status information measured and reported by the UE or information related to an optimal Tx/Rx beam selected by the UE has been received within a predetermined time; and   if the channel status information or the information on the optimal Tx/Rx beam selected by the UE has not been received within the predetermined time, determining that the Tx/Rx beam mismatch occurs.   
     
     
         4 . The method of  claim 1 , wherein the determining whether the Tx/Rx beam mismatch occurs comprises:
 determining whether the optimal Tx/Rx beam has a capability equal to or larger than a first threshold;   if the optimal Tx/Rx beam has the capability equal to or larger than the first threshold, determining whether information on an optimal Tx/Rx beam selected by a base station (BS) has been received within a predetermined time; and   if the information related to the optimal Tx/Rx beam selected by the BS has not been received within the predetermined time, determining that the Tx/Rx beam mismatch occurs.   
     
     
         5 . The method of  claim 1 , wherein the transmitting the compensation information comprises:
 configuring at least one of information related to the UE and information related to the optimal Tx/Rx beam in a broadcasting channel (BCH) region and transmitting the configured information in all beam directions.   
     
     
         6 . The method of  claim 1 , wherein the selecting the new Tx/Rx beam comprises selecting a new DL Tx/Rx beam based on a pre-received uplink (UL) Tx/Rx beam or selecting a new UL Tx/Rx beam based on a pre-received downlink (DL) Tx/Rx beam based on the reciprocality between UL and DL. 
     
     
         7 . The method of  claim 1 , wherein the transmitting the compensation information comprises:
 configuring an identifier of the UE or information derived from the identifier of the UE in a primary broadcasting channel (BCH) region of a downlink (DL) sub-frame;   configuring information related to the identifier of the UE and information related to the optimal Tx/Rx beam in a secondary BCH region of the DL sub-frame; and   transmitting the DL sub-frame including the primary and secondary BCH regions.   
     
     
         8 . The method of  claim 1 , further comprising:
 receiving a downlink (DL) sub-frame including primary and secondary broadcasting channel (BCH) regions;   if bitmap information is included in the primary BCH region, determining a bit related to an identifier of the UE among bits included in a bitmap; and   if the bit related to the identifier of the UE is “1”, setting a Tx/Rx beam indicated by information on the optimal Tx/Rx beam included in the secondary BCH region as a Tx/Rx beam to be used for actual transmission or reception.   
     
     
         9 . The method of  claim 1 , further comprising:
 determining whether the optimal Tx/Rx beam having a capability equal to or larger than a first threshold is identical to a previously selected optimal Tx/Rx beam;   if the optimal Tx/Rx beam is not identical to the previously selected optimal Tx/Rx beam, determining whether the previously selected Tx/Rx beam has a capability equal to or smaller than a second threshold; and   if the previously selected Tx/Rx beam has the capability equal to or smaller than the second threshold, determining that there is a possibility of an occurrence of the Tx/Rx beam mismatch.   
     
     
         10 . The method of  claim 1 , further comprising:
 determining whether a frequency with which the optimal Tx/Rx beam is changed per second is equal to or larger than a preset value; and   if the frequency with which the optimal Tx/Rx beam is changed per second is equal to or larger than the preset value, determining that there is a possibility of the occurrence of the Tx/Rx beam mismatch.   
     
     
         11 . The method of  claim 1 , further comprising:
 determining whether a movement speed of a user equipment (UE) is equal to or faster than a preset speed; and   if the movement speed of the UE is equal to or faster than the preset speed, determining that there is a possibility of the occurrence of the Tx/Rx beam mismatch.   
     
     
         12 . An apparatus for providing an optimal transmission or reception (Tx/Rx) beam in a beamforming system, the apparatus comprising:
 a receiver configured to receive a reference signal and a control signal;   a controller configured to:
 select an optimal Tx/Rx beam that guarantees an optimal channel environment based on the received reference signal and control signal; 
 determine whether a Tx/Rx beam mismatch occurs between the selected optimal Tx/Rx beam and a Tx/Rx beam used for transmitting information on the selected optimal Tx/Rx beam; and 
 if the Tx/Rx beam mismatch occurs, select a new Tx/Rx beam based on pre-received Tx/Rx beam information; and 
   a transmitter configured to transmit compensation information including at least one of information related to a user equipment (UE) and information related to the optimal Tx/Rx beam through the new Tx/Rx beam.   
     
     
         13 . The apparatus of  claim 12 , wherein the controller is configured to:
 determine whether the optimal Tx/Rx beam has a capability equal to or larger than a first threshold;   if the optimal Tx/Rx beam has the capability equal to or larger than the first threshold, determine whether response messages of pre-transmitted control signals or data have been received more than a predetermined number of times or more; and   if the response messages have not been received more than the predetermined number of times or more, determine that the Tx/Rx/bean mismatch occurs.   
     
     
         14 . The apparatus of  claim 12 , wherein the controller is configured to:
 determine whether the optimal Tx/Rx beam has a capability equal to or larger than a first threshold;   if the optimal Tx/Rx beam has the capability equal to or larger than the first threshold, determine whether channel status information measured and reported by the UE or information related to an optimal Tx/Rx beam selected by the UE has been received within a predetermined time; and   if the channel status information or the information on the optimal Tx/Rx beam selected by the UE has not received within the predetermined time, determine that the Tx/Rx beam mismatch occurs.   
     
     
         15 . The apparatus of  claim 12 , wherein the controller is configured to:
 determine whether the optimal Tx/Rx beam has a capability equal to or larger than a first threshold;   if the optimal Tx/Rx beam has the capability equal to or larger than the first threshold, determine whether information on an optimal Tx/Rx beam selected by a base station (BS) has been received within a predetermined time; and   if the information related to the optimal Tx/Rx beam selected by the BS has not been received within the predetermined time, determine that the Tx/Rx beam mismatch occurs.   
     
     
         16 . The apparatus of  claim 12 , wherein the transmitter is configured to:
 configure at least one of information related to the UE and information related to the optimal Tx/Rx beam in a broadcasting channel (BCH) region and transmits the configured information in all beam directions.   
     
     
         17 . The apparatus of  claim 12 , wherein the controller is configured to:
 select a new DL Tx/Rx beam based on a pre-received uplink (UL) Tx/Rx beam, or a new UL Tx/Rx beam based on a pre-received downlink (DL) Tx/Rx beam based on the reciprocality between UL and DL.   
     
     
         18 . The apparatus of  claim 12 , wherein the transmitter is configured to:
 configure an identifier of the UE or information derived from the identifier of the UE in a primary broadcasting channel (BCH) region of a downlink (DL) sub-frame;   configure information related to the identifier of the UE and information related to the optimal Tx/Rx beam in a secondary BCH region of the DL sub-frame; and   transmit the DL sub-frame including the primary and secondary BCH regions.   
     
     
         19 . The apparatus of  claim 12 , wherein:
 the receiver is configured to receive a downlink (DL) sub-frame including primary and secondary broadcasting channel (BCH) regions; and   the controller is configured to:
 if bitmap information is included in the primary BCH region, determine a bit related to an identifier of the UE among bits included in a bitmap; and 
 if the bit related to the identifier of the UE is “1”, set a Tx/Rx beam indicated by information on the optimal Tx/Rx beam included in the secondary BCH region as a Tx/Rx beam to be used for actual transmission or reception. 
   
     
     
         20 . The apparatus of  claim 12 , wherein:
 the controller is further configured to:
 determine whether the optimal Tx/Rx beam having a capability equal to or larger than a first threshold is identical to a previously selected optimal Tx/Rx beam; 
 if the optimal Tx/Rx beam is not identical to the previously selected optimal Tx/Rx beam, determine whether the previously selected Tx/Rx beam has a capability equal to or smaller than a second threshold; and 
 if the previously selected Tx/Rx beam has the capability equal to or smaller than the second threshold, determine that there is a possibility of an occurrence of the Tx/Rx beam mismatch.