Abstract:
Provided are a method and device for three-dimensional channel measurement resource configuration and quality measurement, which relate to the field of wireless communications and are used for solving the problem of how to perform three-dimensional channel quality measurement. In the present invention, a base station selects a channel quality measurement resource used for three-dimensional channel measurement from channel quality measurement resources preconfigured for a terminal, and sends indication information about the selected channel quality measurement resource to the terminal; the terminal receives the indication information, and performs three-dimensional channel quality measurement on corresponding channel quality measurement resources, thereby solving the problem of how to perform three-dimensional channel quality measurement.

Description:
This application is a US National Stage of International Application No. PCT/CN2014/070939, filed on Jan. 21, 2014, designating the United States and claiming the priority to Chinese Patent Application No. 201310045899.4, filed with the State Intellectual Property Office of People&#39;s Republic of China on Feb. 5, 2013 and entitled “Method and device for three-dimensional channel measurement resource configuration and quality measurement”, the content of which is hereby incorporated by reference in its entirety. 
     FIELD 
     The present invention relates to the field of communications and particularly to a method and device for three-dimensional channel measurement resource configuration and quality measurement. 
     BACKGROUND 
     Antennas have been applied on a large scale in reality along with increasing maturation of Active Antenna System (AAS) technologies. The quality of three-dimensional channels cannot be measured in the existing Long Term Evolution (LTE) and Long Term Evolution-Advanced (LTE-A) system, but after the antennas are applied on a large scale, the number of ports controllable by a base station can grow dramatically to 64 or even more, so that the three-dimensional channels can be increasingly applied. It is highly desirable to address the issue of how to measure effectively the quality of three-dimensional channels. 
     The quality of a channel is typically measured using a Cell-specific Reference Signal (CRS) and a Channel State Information-Reference Signal (CSI-RS) in the existing system, where the CRS is transmitted in each sub-frame, and at most four ports are supported; and a User Equipment (UE) can obtain the positions of resources occupied by the CRS according to a broadcast channel and a cell identifier (ID). The CSI-RS is configured periodically, and a transmission periodicity, the number of ports, and the positions of occupied resources are signaled in Radio Resource Control (RRC) signaling; at most eight ports can be supported; and the concept of a process is defined in the LTE-A system, where each process corresponds to one CSI-RS measurement resource, and each UE can be configured with a plurality of processes. 
     Controllable antenna elements are arranged in a two-dimensional pattern in the case of three-dimensional channels, but controllable antenna elements in the existing system are arranged in a linear array. Although multi-port channel measurement can be made by configuring a plurality of CSI-RS resources in the existing system, the CSI-RS resources are independent of each other, so that the UE cannot obtain the overall quality of the three-dimensional channels by jointing measurement results on the plurality of CSI-RS resources, and since the qualities of horizontal and vertical channels in the case of the three-dimensional channels are not totally independent of each other, it is highly desirable to address the issue of how to instruct the UE to obtain the overall information of the three-dimensional channels, and moreover a support of measuring the quality of the three-dimensional channels has been absent in the existing system. 
     SUMMARY 
     Embodiments of the invention provide a method and device for three-dimensional channel measurement configuration and quality measurement so as to address the issue of how to measure the quality of three-dimensional channels. 
     A method for configuring resources for three-dimensional channel measurement includes: 
     selecting, by a base station provided with a two-dimensional array of antennas, channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for a user equipment, wherein each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and 
     transmitting, by the base station for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and transmitting indicators of the selected channel quality measurement resources to the user equipment. 
     A method for three-dimensional channel measurement includes: 
     receiving, by a user equipment, indicators, transmitted by a base station provided with a two-dimensional array of antennas, of channel quality measurement resources for three-dimensional channel measurement, wherein the channel quality measurement resources for three-dimensional channel measurement are selected by the base station from channel quality measurement resources preconfigured for the user equipment, and each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; 
     receiving, by the user equipment, for each of the channel quality measurement resources for three-dimensional channel measurement a channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and making channel quality measurement according to the channel measurement reference signal; 
     obtaining, by the user equipment, three-dimensional channel quality information according to results of the channel quality measurement, and reporting the three-dimensional channel quality information to the base station. 
     A base station provided with a two-dimensional array of antennas includes: 
     a selecting unit configured to select channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for a user equipment, wherein each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and 
     a transmitting unit configured to transmit for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and to transmit indicators of the selected channel quality measurement resources to the user equipment. 
     A user equipment includes: 
     a receiving unit configured to receive indicators, transmitted by a base station provided with a two-dimensional array of antennas, of channel quality measurement resources for three-dimensional channel measurement, wherein the channel quality measurement resources for three-dimensional channel measurement are selected by the base station from channel quality measurement resources preconfigured for the user equipment, and each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; 
     a measuring unit configured to receive for each of the channel quality measurement resources for three-dimensional channel measurement a channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and to make channel quality measurement according to the channel measurement reference signal; 
     a determining unit configured to obtain three-dimensional channel quality information according to results of the channel quality measurement; and 
     a reporting unit configured to report the three-dimensional channel quality information to the base station. 
     A base station includes a two-dimensional array of antennas, a transceiver, a processor, and a memory, wherein: 
     the processor is configured with one or more executable programs to select channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for a user equipment, wherein each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and 
     to transmit for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and to transmit indicators of the selected channel quality measurement resources to the user equipment; and 
     the memory is configured to store the one or more executable programs for configuring the processor. 
     A user equipment includes antennas, a transceiver, a processor, and a memory, wherein: 
     the processor is configured with one or more executable programs to receive indicators, transmitted by a base station provided with a two-dimensional array of antennas, of channel quality measurement resources for three-dimensional channel measurement, through the antennas and the transceiver, wherein the channel quality measurement resources for three-dimensional channel measurement are selected by the base station from channel quality measurement resources preconfigured for the user equipment, and each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; 
     to receive for each of the channel quality measurement resources for three-dimensional channel measurement a channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource through the transceiver and the antennas, to make channel quality measurement according to the channel measurement reference signal, and to obtain three-dimensional channel quality information according to results of the channel quality measurement; and to report the three-dimensional channel quality information to the base station through the transceiver and the antennas; and 
     the memory is configured to store the one or more executable programs for configuring the processor. 
     In the solutions according to the embodiments of the invention, the base station provided with a two-dimensional array of antennas selects channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for the user equipment, transmits indicators of the selected channel quality measurement resources to the user equipment, and transmits for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource; and the user equipment receives the indicators, transmitted by the base station, of the channel quality measurement resources for three-dimensional channel measurement, receives for each of the channel quality measurement resources for three-dimensional channel measurement the channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, makes channel quality measurement according to the channel measurement reference signal; and obtains three-dimensional channel quality information according to all of results of the channel quality measurement, and reports the three-dimensional channel quality information to the base station. As can be apparent, in the solutions, the base station signals the channel quality measurement resources for three-dimensional channel measurement to the user equipment, and the user equipment makes three-dimensional channel quality measurement over the corresponding channel quality measurement resources, to thereby address the issue of how to make three-dimensional channel quality measurement. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a schematic flow chart of a method according to an embodiment of the invention; 
         FIG. 2  illustrates a schematic flow chart of another method according to an embodiment of the invention; 
         FIG. 3  illustrates a schematic general flow chart according to an embodiment of the invention; 
         FIG. 4  illustrates a schematic diagram of mapping of measurement resources to an array of ports according to an embodiment of the invention; 
         FIG. 5  illustrates another schematic diagram of mapping of measurement resources to an array of ports according to an embodiment of the invention; 
         FIG. 6  illustrates a schematic structural diagram of a base station according to an embodiment of the invention; 
         FIG. 7  illustrates a schematic structural diagram of a user equipment according to an embodiment of the invention; 
         FIG. 8  illustrates a schematic structural diagram of a base station according to another embodiment of the invention; and 
         FIG. 9  illustrates a schematic structural diagram of a user equipment according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In order to provide a support of measuring the quality of three-dimensional channels at the user equipment side, an embodiment of the method provides a method for configuring measurement resources of three-dimensional channels. 
     Referring to  FIG. 1 , a method for configuring resources for three-dimensional channel measurement according to an embodiment of the invention includes the following operations: 
     Operation  10 : A base station provided with a two-dimensional array of antennas selects channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for a user equipment, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port. 
     Here the time-frequency resource position corresponding to the channel quality measurement resource can be determined by a time-frequency resource position occupied by a channel quality measurement reference signal in a transmission sub-frame, a sub-frame offset, a measurement periodicity, and other parameters thereof. For example, if the time-frequency resource position occupied by the channel quality measurement reference signal in the transmission sub-frame includes two Resource Elements (REs) on the sixth and seventh Orthogonal Frequency Division Multiplexing (OFDM) symbols corresponding to the third carrier on each Physical Resource Block (PRB) in the first timeslot, the measurement periodicity is five sub-frames, and the sub-frame offset is 2, then the time-frequency resource position corresponding to the channel quality measurement resource includes two REs on the sixth and seventh OFDM symbols corresponding to the third carrier on each PRB in the first timeslot in the second sub-frame in a periodicity. The port or ports corresponding to the channel quality measurement resource can be determined by the number of ports. For example, if the number of ports is 1, then the port corresponding to the channel quality measurement resource includes the port  0 ; if the number of ports is 2, then the ports corresponding to the channel quality measurement resource include the ports  0  and  1 ; if the number of ports is 4, then the ports corresponding to the channel quality measurement resource include the ports  0 ,  1 ,  2  and  3 ; and if the number of ports is 8, then the ports corresponding to the channel quality measurement resource include the ports  0 ,  1 ,  2 ,  3 ,  4 ,  5 ,  6  and  7 . 
     Operation  11 : The base station transmits indicators of the selected channel quality measurement resources to the user equipment, and transmits for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource. 
     Furthermore before the base station selects the channel quality measurement resources for three-dimensional channel measurement from the channel quality measurement resources preconfigured for the user equipment, the base station configures the user equipment with a plurality of channel quality measurement resources and numbers the measurement resources, where each of the configured plurality of channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and then the base station transmits indicators of the configured plurality of channel quality measurement resources to the user equipment in Radio Resource Control (RRC) signaling. The indicator of each of the configured plurality of channel quality measurement resources can include parameters representing the time-frequency resource position corresponding to the channel quality measurement resource, the number of ports corresponding to the channel quality measurement resource, etc.; and the serial number of each of the configured plurality of channel quality measurement resources can also be concurrently transmitted to the user equipment, so that the indicators of the selected channel quality measurement resources in the operation  11  can be the serial numbers of the selected channel quality measurement resources. 
     Particularly in the operation  10 , the base station can select the channel quality measurement resources for three-dimensional channel measurement from the channel quality measurement resources preconfigured for the user equipment particularly as follows: 
     The base station selects at least one of the channel quality measurement resources preconfigured for the user equipment as a channel quality measurement resource for three-dimensional channel measurement, where the sum of the numbers of ports corresponding to the respective selected channel quality measurement resource is equal to the total number of ports to be measured for three-dimensional-Multiple Input Multiple Output (3D-MIMO). Here the total number of ports to be measured for 3D-MIMO refers to the total number of ports configured at the base station side to obtain the quality of three-dimensional spatial channels in the case of 3D-MIMO, where the number of ports is more than 1. 
     In this method, the channel quality measurement resource can be a Channel State Information-Reference Signal (CSI-RS) resource; and the channel measurement reference signal is a CSI-RS. 
     In order to address the issue of how to measure the quality of three-dimensional channels, an embodiment of the invention provides a method for three-dimensional channel measurement. 
     Referring to  FIG. 2 , an embodiment of the invention provides a method for three-dimensional channel measurement, which includes the following operations: 
     Operation  20 : A user equipment receives indicators, transmitted by a base station provided with a two-dimensional array of antennas, of channel quality measurement resources for three-dimensional channel measurement, where the channel quality measurement resources for three-dimensional channel measurement are selected by the base station from channel quality measurement resources preconfigured for the user equipment, and each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port. 
     Here the time-frequency resource position corresponding to the channel quality measurement resource can be determined by a time-frequency resource position occupied by a channel quality measurement reference signal in a transmission sub-frame, a sub-frame offset, a measurement periodicity, and other parameters thereof. For example, if the time-frequency resource position occupied by the channel quality measurement reference signal in the transmission sub-frame includes two REs on the sixth and seventh OFDM symbols corresponding to the third carrier on each PRB in the first timeslot, the measurement periodicity is five sub-frames, and the sub-frame offset is 2, then the time-frequency resource position corresponding to the channel quality measurement resource includes two REs on the sixth and seventh OFDM symbols corresponding to the third carrier on each PRB in the first timeslot in the second sub-frame in a periodicity. The port or ports corresponding to the channel quality measurement resource can be determined by the number of ports. For example, if the number of ports is 1, then the port corresponding to the channel quality measurement resource includes the port  0 ; if the number of ports is 2, then the ports corresponding to the channel quality measurement resource include the ports  0  and  1 ; if the number of ports is 4, then the ports corresponding to the channel quality measurement resource include the ports  0 ,  1 ,  2  and  3 ; and if the number of ports is 8, then the ports corresponding to the channel quality measurement resource include the ports  0 ,  1 ,  2 ,  3 ,  4 ,  5 ,  6  and  7 . 
     Operation  21 : The user equipment receives for each of the channel quality measurement resources for three-dimensional channel measurement a channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and makes channel quality measurement according to the channel measurement reference signal. 
     Operation  22 : The user equipment obtains three-dimensional channel quality information according to results of the channel quality measurement, and reports the three-dimensional channel quality information to the base station. 
     Furthermore before the user equipment receives the indicators, transmitted by the base station, the channel quality measurement resources for three-dimensional channel measurement, the user equipment can receive indicators of a plurality of channel quality measurement resources configured by the base station, where each of the plurality of channel quality measurement resources corresponds to one time-frequency resource position and at least one port. The indicator of each of the configured plurality of channel quality measurement resources can include parameters representing the time-frequency resource position corresponding to the channel quality measurement resource, the number of ports corresponding to the channel quality measurement resource, etc.; and the user equipment can further concurrently receive the serial number of each of the configured plurality of channel quality measurement resources, so that the indicators of the channel quality measurement resources for three-dimensional channel measurement received by the user equipment in the operation  20  can be the serial numbers of the channel quality measurement resources for three-dimensional channel measurement. 
     Particularly the sum of the numbers of ports corresponding to the respective channel quality measurement resources for three-dimensional channel measurement is equal to the total number of ports to be measured for 3D-MIMO. Here the total number of ports to be measured for 3D-MIMO refers to the total number of ports configured at the base station side to obtain the quality of three-dimensional spatial channels in the case of 3D-MIMO, where the number of ports is more than 1. Correspondingly the user equipment can obtain the three-dimensional channel quality information according to the results of the channel quality measurement in the operation  22  particularly as follows: 
     The user equipment determines the position or positions, in the two-dimensional array of antennas of the base station, of the port or ports corresponding to each of the channel quality measurement resources for three-dimensional channel measurement according to preconfigured information; 
     The user equipment obtains for each row in the two-dimensional array of antennas of the base station a channel correlation matrix corresponding to the row of ports according to results of the channel quality measurement on the respective ports in the row; and obtains horizontal Pre-coding Matrix Indicator (PMI) information according to the channel correlation matrixes corresponding to the respective rows of ports, and obtains horizontal Channel Quality Indicator (CQI) information according to the PMI information (reference can be made to the 3GPP TS 36.213 protocol for details thereof); and 
     The user equipment obtains for each column in the two-dimensional array of antennas of the base station a channel correlation matrix corresponding to the column of ports according to results of the channel quality measurement on the respective ports in the column; and obtains vertical PMI information according to the channel correlation matrixes corresponding to the respective columns of ports, and obtains vertical CQI information according to the PMI information. 
     Particularly the user equipment can obtain the channel correlation matrix R HH     n    corresponding to the n-th row of ports in the two-dimensional array of antennas of the base station in Equation 1 below:
 
 R   HH     n   =( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 ) H *( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 );  Equation 1
 
     Where H n,m  represents a channel quality measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where n ranges from 0 (inclusive) to N−1 (inclusive), and m ranges from 0 (inclusive) to M−1 (inclusive), where N represents the total number of rows in the two-dimensional array of antennas of the base station, and M represents the total number of columns in the two-dimensional array of antennas of the base station; and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where h n,m,r  represents a channel quality measurement result on the port in the n-th row and in the m-th column over the r-th receive antenna, where r ranges from 0 (inclusive) to R−1 (inclusive), where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. 
     Particularly the user equipment can obtain the horizontal PMI information according to the channel correlation matrixes corresponding to the respective rows of ports particularly as follows: 
     The user equipment obtains an average matrix R HH  of the channel correlation matrixes corresponding to the respective rows of ports in Equation 2 below: 
                       R   HH     =       1   N     ⁢       ∑     n   =   0       N   -   1       ⁢     R     HH   n             ;           Equation   ⁢           ⁢   2               
and
 
     The user equipment obtains the horizontal PMI information by decomposing the average matrix R HH  (for example, decomposing R HH  through SVD decomposition method). 
     Particularly the user equipment can obtain the channel correlation matrix R HH     m    corresponding to the m-th column of ports in the two-dimensional array of antennas of the base station in Equation 3 below:
 
 R   HH     m   =( H   0,m   ,H   1,m   , . . . ,H   N−1,m ) H *( H   0,m   ,H   1,m   , . . . ,H   N−1,m );  Equation 3
 
     Where H n,m  represents a channel quality measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where n ranges from 0 (inclusive) to N−1 (inclusive), and m ranges from 0 (inclusive) to M−1 (inclusive), where N represents the total number of rows in the two-dimensional array of antennas of the base station, and M represents the total number of columns in the two-dimensional array of antennas of the base station; and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where h n,m,r  represents a channel quality measurement result on the port in the n-th row and in the m-th column over the r-th receive antenna, where r ranges from 0 (inclusive) to R−1 (inclusive), where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. 
     Particularly the user equipment can obtain the vertical PMI information according to the channel correlation matrixes corresponding to the respective columns of ports particularly as follows: 
     The user equipment obtains an average matrix R HH  of the channel correlation matrixes corresponding to the respective columns of ports in Equation 4 below: 
                       R   HH     =       1   M     ⁢       ∑     m   =   0       M   -   1       ⁢     R     HH   m             ;           Equation   ⁢           ⁢   4               
and
 
     The user equipment obtains the vertical PMI information by decomposing the average matrix R HH . 
     In this method, the channel quality measurement resource can be a CSI-RS resource; 
     and the channel measurement reference signal is a CSI-RS. 
     The invention will be described below in details in connection with a particular application scenario: 
     As illustrated in  FIG. 3 : 
     Operation  1 : A base station pre-configures channel quality measurement resources including K CSI-RS resources for a UE and numbers the CSI-RS resource sequentially by {0, 1, 2, 3, . . . , K−1}. There are corresponding parameters for each of the CSI-RS resources, e.g., a time-frequency resource position occupied by the CSI-RS resource in a transmission sub-frame, a sub-frame offset, a measurement periodicity, the number of ports, etc. The base station signals the configured CSI-RS resources to the UE in RRC signaling together with the serial numbers corresponding to the respective CSI-RS resources, where K represents an integer more than 1. 
     Operation  2 : Based on the consideration that there are influences of the CSI-RS resources on a system overhead and radio channels may vary differently, a CSI-RS may not be transmitted over all the pre-configured CSI-RS resources, and the quality of three-dimensional channels may not be measured over all the CSI-RS resources even if the CSI-RS is transmitted over all the CSI-RS resources, instead the CSI-RS may be transmitted over the CSI-RS resources over which the quality of three-dimensional channels needs to be measured, or the quality of three-dimensional channels may be measured over a part of the CSI-RS resources. The number of selected CSI-RS resources for three-dimensional channel measurement is dependent upon the total number of ports to be measured for 3D-MIMO, and the respective CSI-RS resources may correspond to different numbers of ports, but the sum of the numbers of ports of all the selected CSI-RS resources for three-dimensional channel measurement is equal to the total number of ports to be measured for 3D-MIMO. The selected CSI-RS resources for three-dimensional channel measurement need to be signaled to the UE in RRC signaling or DCI signaling. 
     Operation  3 : The UE makes three-dimensional channel quality measurement over the CSI-RS resources for three-dimensional channel measurement according to the received control signaling. In order to lower a feedback overhead and to facilitate a design of a codebook, vertical and horizontal channel quality information can be fed back separately. H n,m  represents a channel measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where N represents the total number of rows in the two-dimensional array of antennas, and M represents the total number of columns in the two-dimensional array of antennas. H n,m  represents a column vector, and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. For horizontal channel quality measurement, firstly a channel correlation matrix corresponding to each row of ports is obtained in the equation below of:
 
 R   HH     n   =( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 ) H *( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 );
 
     The obtained N channel correlation matrixes are averaged in the equation below of: 
                 R   HH     =       1   N     ⁢       ∑     n   =   0       N   -   1       ⁢     R     HH   n             ;         
and
 
     Horizontal PMIs can be obtained by decomposing and calculating the matrix R HH , and CQIs corresponding to the PMIs can be calculated. 
     For vertical channel quality measurement, firstly a channel correlation matrix corresponding to each column of ports is obtained in the equation below of:
 
 R   HH     m   =( H   0,m   ,H   1,m   , . . . ,H   N−1,m ) H *( H   0,m   ,H   1,m   , . . . ,H   N−1,m );
 
     The obtained M channel correlation matrixes are averaged in the equation below of: 
                 R   HH     =       1   M     ⁢       ∑     m   =   0       M   -   1       ⁢     R     HH   m             ;         
and
 
     Finally vertical PMIs can be obtained by decomposing and calculating the matrix R HH , and CQIs corresponding to the PMIs can be calculated. 
     Operation  4 : The UE reports the horizontal CQIs and the vertical CQIs to the base station. 
     The invention will be described below in details in connection with another particular application scenario: 
     In a first operation, a base station pre-configures channel quality measurement resources including K CSI-RS resources for a UE and numbers the CSI-RS resource sequentially by {0, 1, 2, 3, . . . , K−1}. For example, if the channel quality measurement resources include eight CSI-RS resources, then the eight CSI-RS resources are numbered sequentially by {0, 1, 2, 3, 4, 5, 6, 7}. There are corresponding parameters for each of the CSI-RS resources, e.g., a time-frequency resource position occupied by the CSI-RS resource in a transmission sub-frame, a sub-frame offset, a measurement periodicity, the number of ports, etc. The base station signals the configured CSI-RS resources to the UE in RRC signaling together with the serial numbers corresponding to the respective CSI-RS resources. 
     In a second operation, based on the consideration that there are influences of the CSI-RS resources on a system overhead and radio channels may vary differently, a CSI-RS may not be transmitted over all the pre-configured CSI-RS resources, and the quality of three-dimensional channels may not be measured over all the CSI-RS resources even if the CSI-RS is transmitted over all the CSI-RS resources, instead the CSI-RS may be transmitted over the CSI-RS resources over which the quality of three-dimensional channels needs to be measured, or the quality of three-dimensional channels may be measured over a part of the CSI-RS resources. 
     The number of selected CSI-RS resources for three-dimensional channel measurement is dependent upon the total number of ports to be measured for 3D-MIMO, and the total number of ports to be measured for 3D-MIMO may take the value of 8, 16, 32, 64, etc. If each of the CSI-RS resources corresponds to four ports, then the numbers of CSI-RS resources required for the four kinds of total number of ports are 2, 4, 8 and 16 respectively; and if each of the CSI-RS resources corresponds to eight ports, then the numbers of CSI-RS resources required for the four kinds of total number of ports are 1, 2, 4 and 8 respectively. However, the respective CSI-RS resources may correspond to different numbers of ports, while the sum of the numbers of ports of all the CSI-RS resources is equal to the total number of ports to be measured for 3D-MIMO. As illustrated in  FIG. 4 , the total number of ports to be measured for 3D-MIMO is 32, and seven CSI-RS resources are selected, where measurement resources  0  and  1  include an 8-port CSI-RS resource respectively, measurement resources  2 ,  3  and  5  include a 4-port CSI-RS resource respectively, and measurement resources  4  and  6  include a 2-port CSI-RS resource respectively.  FIG. 5  illustrates another configuration including four 8-port CSI-RS resources. 
     The selected CSI-RS resources for three-dimensional channel measurement are signaled to the UE in RRC signaling or DCI signaling. For example, if there are eight 8-port CSI-RS resources, then they can be signaled in 2-bit RRC signaling or DCI signaling as depicted in Table 1. If the signaling indicates {1, 0}, then three-dimensional channel quality measurement can be made jointly over the 0 th  to 3 rd  CSI-RS resources. 
     
       
         
               
               
             
           
               
                   
               
               
                   
                 Resources for three-dimensional 
               
               
                 Signaling format 
                 channel quality measurement 
               
               
                   
               
             
             
               
                 00 
                 {0} 
               
               
                 01 
                 {0, 1} 
               
               
                 10 
                 {0, 1, 2, 3} 
               
               
                 11 
                 {0, 1, 2, 3, 4, 5, 6, 7} 
               
               
                   
               
             
          
         
       
     
     In order to configure more flexibly the CSI-RS resources over which three-dimensional channels need to be measured, they can alternatively be indicated in a bitmap. For example, if eight CSI-RS resources are configured, then the eight CSI-RS resources can be indicated respectively by 8-bit signaling, for example, if the signaling indicates {1, 1, 1, 1, 1, 1, 1, 0}, then three-dimensional channel quality measurement can be made jointly over the 0 th  to 6 th  CSI-RS resources. 
     In a third operation, the UE makes three-dimensional channel quality measurement over the corresponding CSI-RS resources according to the received control signaling. In order to lower a feedback overhead and to facilitate a design of a codebook, vertical and horizontal channel quality information can be fed back separately. As illustrated in  FIG. 4 , channel qualities on 32 ports need to be measured at the base station side over seven CSI-RS resources with the port configuration illustrated in  FIG. 4 , and the UE obtains three-dimensional channel quality information by measuring the channel qualities on the corresponding ports, although the same will apply to alternative configurations. 
     H n,m  represents a channel measurement value on a port in the n-th row and in the m-th column in the two-dimensional array, where N represents the total number of rows in the two-dimensional array of antennas, and M represents the total number of columns in the two-dimensional array of antennas. H n,m  represents a column vector, and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. Referring to  FIG. 4  as an example, n takes the value of {0, 1, 2, 3}, and m takes the value of {0, 1, 2, 3, 4, 5, 6, 7}. For horizontal channel quality measurement, firstly a channel correlation matrix corresponding to each row of ports is obtained:
 
 R   HH     n   =( H   n,0   ,H   n,1   ,H   n,2   ,H   n,3   ,H   n,4   ,H   n,5   ,H   n,6   ,H   n,7 ) H *( H   n,0   ,H   n,1   ,H   n,2   ,H   n,3   ,H   n,4   ,H   n,5   ,H   n,6   ,H   n,7 );
 
     The obtained N channel correlation matrixes are averaged: 
                 R   HH     =       1   N     ⁢       ∑     n   =   0       N   -   1       ⁢     R     HH   n             ;         
and
 
     Horizontal PMIs can be obtained by decomposing and calculating the matrix R HH , and corresponding CQIs can be calculated. 
     For vertical channel quality measurement, firstly a channel correlation matrix corresponding to each column of ports is obtained:
 
 R   HH     m   =( H   0,m   ,H   1,m   ,H   2,m   ,H   3,m ) H *( H   0,m   ,H   1,m   ,H   2,m   ,H   3,m );
 
     The obtained M channel correlation matrixes are averaged: 
                 R   HH     =       1   M     ⁢       ∑     m   =   0       M   -   1       ⁢     R     HH   m             ;         
and
 
     Finally vertical PMIs can be obtained by decomposing and calculating the matrix R HH , and corresponding CQIs can be calculated. 
     In a fourth operation, the UE reports measurement results to the base station. 
     Referring to  FIG. 6 , an embodiment of the invention provides a base station which can perform the method for configuring resources for three-dimensional channel measurement according to the embodiment of the invention. The base station provided with a two-dimensional array of antennas includes: 
     A selecting unit  60  is configured to select channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for a user equipment, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and 
     A transmitting unit  61  is configured to transmit indicators of the selected channel quality measurement resources to the user equipment, and to transmit for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource. 
     Furthermore the base station further includes: 
     A configuring unit  62  is configured to configure the user equipment with a plurality of channel quality measurement resources, and to number the measurement resources, before the channel quality measurement resources for three-dimensional channel measurement are selected from the channel quality measurement resources preconfigured for the user equipment, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and 
     To transmit indicators of the configured plurality of channel quality measurement resources to the user equipment in Radio Resource Control (RRC) signaling. 
     Furthermore the selecting unit  60  is configured: 
     To select at least one of the channel quality measurement resources preconfigured for the user equipment as a channel quality measurement resource for three-dimensional channel measurement, where the sum of the numbers of ports corresponding to the respective selected channel quality measurement resource is equal to the total number of ports to be measured for 3D-MIMO. 
     Furthermore the channel quality measurement resource is a Channel State Information-Reference Signal (CSI-RS) resource; and the channel measurement reference signal is a CSI-RS. 
     Referring to  FIG. 7 , an embodiment of the invention provides a user equipment which can perform the method for three-dimensional channel measurement according to the embodiment of the invention. The user equipment includes: 
     A receiving unit  70  is configured to receive indicators, transmitted by a base station provided with a two-dimensional array of antennas, of channel quality measurement resources for three-dimensional channel measurement, where the channel quality measurement resources for three-dimensional channel measurement are selected by the base station from channel quality measurement resources preconfigured for the user equipment, and each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; 
     A measuring unit  71  is configured to receive for each of the channel quality measurement resources for three-dimensional channel measurement a channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and to make channel quality measurement according to the channel measurement reference signal; 
     A determining unit  72  is configured to obtain three-dimensional channel quality information according to results of the channel quality measurement; and 
     A reporting unit  73  is configured to report the three-dimensional channel quality information to the base station. 
     Furthermore the receiving unit  70  is further configured: 
     To receive indicators of a plurality of channel quality measurement resources configured by the base station before receiving the indicators, transmitted by the base station, the channel quality measurement resources for three-dimensional channel measurement, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port. 
     Furthermore the sum of the numbers of ports corresponding to the respective channel quality measurement resources for three-dimensional channel measurement is equal to the total number of ports to be measured for 3D-MIMO; and the determining unit  72  is configured: 
     To determine the position or positions, in the two-dimensional array of antennas of the base station, of the port or ports corresponding to each of the channel quality measurement resources for three-dimensional channel measurement; 
     To obtain for each row in the two-dimensional array of antennas of the base station a channel correlation matrix corresponding to the row of ports according to results of the channel quality measurement on the respective ports in the row; and to obtain horizontal Pre-coding Matrix Indicator (PMI) information according to the channel correlation matrixes corresponding to the respective rows of ports, and to obtain horizontal Channel Quality Indicator (CQI) information according to the PMI information; and 
     To obtain for each column in the two-dimensional array of antennas of the base station a channel correlation matrix corresponding to the column of ports according to results of the channel quality measurement on the respective ports in the column; and to obtain vertical PMI information according to the channel correlation matrixes corresponding to the respective columns of ports, and to obtain vertical CQI information according to the PMI information. 
     Furthermore the determining unit  72  is configured: 
     To obtain the channel correlation matrix R HH     n    corresponding to the n-th row of ports in the two-dimensional array of antennas of the base station in Equation 1 below:
 
 R   HH     n   =( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 ) H *( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 );  Equation 1
 
     Where H n,m  represents a channel quality measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where n ranges from 0 (inclusive) to N−1 (inclusive), and m ranges from 0 (inclusive) to M−1 (inclusive), where N represents the total number of rows in the two-dimensional array of antennas of the base station, and M represents the total number of columns in the two-dimensional array of antennas of the base station; and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where h n,m,r  represents a channel quality measurement result on the port in the n-th row and in the m-th column over the r-th receive antenna, where r ranges from 0 (inclusive) to R−1 (inclusive), where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. 
     Furthermore the determining unit  72  is configured: 
     To obtain an average matrix R HH  of the channel correlation matrixes corresponding to the respective rows of ports in Equation 2 below: 
                       R   HH     =       1   N     ⁢       ∑     n   =   0       N   -   1       ⁢     R     HH   n             ;           Equation   ⁢           ⁢   2               
and
 
     To obtain the horizontal PMI information by decomposing the average matrix R HH . 
     Furthermore the determining unit  72  is configured: 
     To obtain the channel correlation matrix R HH     m    corresponding to the m-th column of ports in the two-dimensional array of antennas of the base station in Equation 3 below:
 
 R   HH     m   =( H   0,m   ,H   1,m   , . . . ,H   N−1,m ) H *( H   0,m   ,H   1,m   , . . . ,H   N−1,m );  Equation 3
 
     Where H n,m  represents a channel quality measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where n ranges from 0 (inclusive) to N−1 (inclusive), and m ranges from 0 (inclusive) to M−1 (inclusive), where N represents the total number of rows in the two-dimensional array of antennas of the base station, and M represents the total number of columns in the two-dimensional array of antennas of the base station; and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where h n,m,r  represents a channel quality measurement result on the port in the n-th row and in the m-th column over the r-th receive antenna, where r ranges from 0 (inclusive) to R−1 (inclusive), where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. 
     Furthermore the determining unit  72  is configured: 
     To obtain an average matrix R HH  of the channel correlation matrixes corresponding to the respective columns of ports in Equation 4 below: 
                       R   HH     =       1   M     ⁢       ∑     m   =   0       M   -   1       ⁢     R     HH   m             ;           Equation   ⁢           ⁢   4               
and
 
     To obtain the vertical PMI information by decomposing the average matrix R HH . 
     Furthermore the channel quality measurement resource is a Channel State Information-Reference Signal (CSI-RS) resource; and the channel measurement reference signal is a CSI-RS. 
     Referring to  FIG. 8 , an embodiment of the invention further provides a base station which can perform the method for configuring resources for three-dimensional channel measurement according to the embodiment of the invention. The base station can include a two-dimensional array of antennas  81 , a transceiver  82 , a processor  83 , and a memory  84 . 
     The transceiver  82  can include as needed in practice a baseband processing component, a radio frequency processing component, and other devices for transmitting related information. 
     The processor  83  is configured with one or more executable programs to select channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for a user equipment, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and to transmit for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource, and to transmit indicators of the selected channel quality measurement resources to the user equipment; and 
     The memory  84  is configured to store the one or more executable programs for configuring the processor  83 . 
     Optionally the processor  83  is further configured to configure the user equipment with a plurality of channel quality measurement resources, and to number the measurement resources, before selecting the channel quality measurement resources for three-dimensional channel measurement from the channel quality measurement resources preconfigured for the user equipment, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; and to transmit indicators of the configured plurality of channel quality measurement resources to the user equipment in Radio Resource Control (RRC) signaling. 
     Preferably the processor  83  is configured to select at least one of the channel quality measurement resources preconfigured for the user equipment as a channel quality measurement resource for three-dimensional channel measurement, where the sum of the numbers of ports corresponding to the respective selected channel quality measurement resource is equal to the total number of ports to be measured for 3D-MIMO. 
     Preferably the channel quality measurement resource is a CSI-RS resource; and the channel measurement reference signal is a CSI-RS. 
     Referring to  FIG. 9 , an embodiment of the invention further provides a user equipment which can perform the method for three-dimensional channel measurement according to the embodiment of the invention. The user equipment can include antennas  91 , a transceiver  92 , a processor  93  and a memory  94 . 
     The transceiver  92  can include as needed in practice a baseband processing component, a radio frequency processing component, and other devices for transmitting related information. 
     The processor  93  is configured with one or more executable programs to receive indicators, transmitted by a base station provided with a two-dimensional array of antennas, of channel quality measurement resources for three-dimensional channel measurement, through the antennas and the transceiver, where the channel quality measurement resources for three-dimensional channel measurement are selected by the base station from channel quality measurement resources preconfigured for the user equipment, and each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port; 
     To receive for each of the channel quality measurement resources for three-dimensional channel measurement a channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource through the transceiver and the antennas, to make channel quality measurement according to the channel measurement reference signal, and to obtain three-dimensional channel quality information according to results of the channel quality measurement; and to report the three-dimensional channel quality information to the base station through the transceiver and the antennas. 
     The memory  94  is configured to store the one or more executable programs for configuring the processor  93 . 
     Furthermore the processor  93  is further configured with an executable program to receive indicators of a plurality of channel quality measurement resources configured by the base station before receiving the indicators, transmitted by the base station, the channel quality measurement resources for three-dimensional channel measurement, where each of the channel quality measurement resources corresponds to one time-frequency resource position and at least one port. 
     Preferably the sum of the numbers of ports corresponding to the respective channel quality measurement resources for three-dimensional channel measurement is equal to the total number of ports to be measured for 3D-MIMO; and the processor  93  is further configured with an executable program: 
     To determine the position or positions, in the two-dimensional array of antennas of the base station, of the port or ports corresponding to each of the channel quality measurement resources for three-dimensional channel measurement; 
     To obtain for each row in the two-dimensional array of antennas of the base station a channel correlation matrix corresponding to the row of ports according to results of the channel quality measurement on the respective ports in the row; and to obtain horizontal Pre-coding Matrix Indicator (PMI) information according to the channel correlation matrixes corresponding to the respective rows of ports, and to obtain horizontal Channel Quality Indicator (CQI) information according to the PMI information; and 
     To obtain for each column in the two-dimensional array of antennas of the base station a channel correlation matrix corresponding to the column of ports according to results of the channel quality measurement on the respective ports in the column; and to obtain vertical PMI information according to the channel correlation matrixes corresponding to the respective columns of ports, and to obtain vertical CQI information according to the PMI information. 
     Preferably the processor  93  is further configured with an executable program: 
     To obtain the channel correlation matrix R HH     n    corresponding to the n-th row of ports in the two-dimensional array of antennas of the base station in Equation 1 below:
 
 R   HH     n   =( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 ) H *( H   n,0   ,H   n,1   ,H   n,2   , . . . ,H   n,M−1 );  Equation 1
 
     Where H n,m  represents a channel quality measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where n ranges from 0 (inclusive) to N−1 (inclusive), and m ranges from 0 (inclusive) to M−1 (inclusive), where N represents the total number of rows in the two-dimensional array of antennas of the base station, and M represents the total number of columns in the two-dimensional array of antennas of the base station; and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where h n,m,r  represents a channel quality measurement result on the port in the n-th row and in the m-th column over the r-th receive antenna, where r ranges from 0 (inclusive) to R−1 (inclusive), where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. 
     Preferably the processor  93  is further configured with an executable program: 
     To obtain an average matrix R HH  of the channel correlation matrixes corresponding to the respective rows of ports in Equation 2 below: 
                       R   HH     =       1   N     ⁢       ∑     n   =   0       N   -   1       ⁢     R     HH   n             ;           Equation   ⁢           ⁢   2               
and
 
     To obtain the horizontal PMI information by decomposing the average matrix R HH . 
     Preferably the processor  93  is further configured with an executable program: 
     To obtain the channel correlation matrix R HH     m    corresponding to the m-th column of ports in the two-dimensional array of antennas of the base station in Equation 3 below:
 
 R   HH     m   =( H   0,m   ,H   1,m   , . . . ,H   N−1,m ) H *( H   0,m   ,H   1,m   , . . . ,H   N−1,m );  Equation 3
 
     Where H n,m  represents a channel quality measurement value on a port in the n-th row and in the m-th column in the two-dimensional array of antennas of the base station, where n ranges from 0 (inclusive) to N−1 (inclusive), and m ranges from 0 (inclusive) to M−1 (inclusive), where N represents the total number of rows in the two-dimensional array of antennas of the base station, and M represents the total number of columns in the two-dimensional array of antennas of the base station; and H n,m =[h n,m,0 , h n,m,1 , . . . , h n,m,R−1 ] T , where h n,m,r  represents a channel quality measurement result on the port in the n-th row and in the m-th column over the r-th receive antenna, where r ranges from 0 (inclusive) to R−1 (inclusive), where R represents the total number of receive antennas of the user equipment, and the superscript T represents transposition of the matrix. 
     Preferably the processor  93  is further configured with an executable program: 
     To obtain an average matrix R HH  of the channel correlation matrixes corresponding to the respective columns of ports in Equation 4 below: 
                       R   HH     =       1   M     ⁢       ∑     m   =   0       M   -   1       ⁢     R     HH   m             ;           Equation   ⁢           ⁢   4               
and
 
     To obtain the vertical PMI information by decomposing the average matrix R HH . 
     Preferably the channel quality measurement resource is a CSI-RS resource; and the channel measurement reference signal is a CSI-RS. 
     In summary, advantageous effects of the invention include: 
     In the solutions according to the embodiments of the invention, the base station provided with a two-dimensional array of antennas selects channel quality measurement resources for three-dimensional channel measurement from channel quality measurement resources preconfigured for the user equipment, transmits indicators of the selected channel quality measurement resources to the user equipment, and transmits for each of the selected channel quality measurement resources a channel measurement reference signal to the user equipment via the port or ports corresponding to the channel quality measurement resource on the time-frequency resource position corresponding to the channel quality measurement resource; and the user equipment receives the indicators, transmitted by the base station, of the channel quality measurement resources for three-dimensional channel measurement, receives for each of the channel quality measurement resources for three-dimensional channel measurement the channel measurement reference signal transmitted by the base station via the port or ports corresponding to the channel quality measurement resources on the time-frequency resource position corresponding to the channel quality measurement resource, makes channel quality measurement according to the channel measurement reference signal; and obtains three-dimensional channel quality information according to all of results of the channel quality measurement, and reports the three-dimensional channel quality information to the base station. As can be apparent, in the solutions, the base station signals the channel quality measurement resources for three-dimensional channel measurement to the user equipment, and the user equipment makes three-dimensional channel quality measurement over the corresponding channel quality measurement resources, to thereby address the issue of how to make three-dimensional channel quality measurement. 
     The invention has been described in a flow chart and/or a block diagram of the method, the device (system) and the computer program product according to the embodiments of the invention. It shall be appreciated that respective flows and/or blocks in the flow chart and/or the block diagram and combinations of the flows and/or the blocks in the flow chart and/or the block diagram can be embodied in computer program instructions. These computer program instructions can be loaded onto a general-purpose computer, a specific-purpose computer, an embedded processor or a processor of another programmable data processing device to produce a machine so that the instructions executed on the computer or the processor of the other programmable data processing device create means for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
     These computer program instructions can also be stored into a computer readable memory capable of directing the computer or the other programmable data processing device to operate in a specific manner so that the instructions stored in the computer readable memory create an article of manufacture including instruction means which perform the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
     These computer program instructions can also be loaded onto the computer or the other programmable data processing device so that a series of operational operations are performed on the computer or the other programmable data processing device to create a computer implemented process so that the instructions executed on the computer or the other programmable device provide operations for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
     Although the preferred embodiments of the invention have been described, those skilled in the art benefiting from the underlying inventive concept can make additional modifications and variations to these embodiments. Therefore the appended claims are intended to be construed as encompassing the preferred embodiments and all the modifications and variations coming into the scope of the invention. 
     Evidently those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus the invention is also intended to encompass these modifications and variations thereto so long as the modifications and variations come into the scope of the claims appended to the invention and their equivalents.