Patent Publication Number: US-2019190585-A1

Title: Communication system, coordinator and controlling method thereof

Description:
This application claims the benefit of Taiwan application Serial No. 106143902, filed Dec. 14, 2017, the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates in general to a communication system, a coordinator and a controlling method thereof. 
     BACKGROUND 
     In a traditional WiFi system adopted the smart antenna technology, a plurality of antennas with different radiation directions are disposed in a base station for selection. An antenna selection method is provided to select the best antenna for improving the data communication efficiency. However, the smart antenna technology was adapted in a single base station and only one antenna in the system can be used for communication. Therefore, the diversity cannot be improved. Moreover, an antenna array may be used for improving the data communication efficiency. However, the antenna size of the antenna array is huge and the corresponding implementation cost is expensive, so it is not applicable for the small cell. 
     SUMMARY 
     The disclosure is directed to a communication system, a coordinator and a controlling method thereof. 
     According to one embodiment, a controlling method of a communication system is provided. The communication system includes a plurality of Remote Radio Heads (RRHs). Each of the RRHs is electrically connected to a plurality of antennas. The communication system is used for one or more user equipments. The controlling method includes the following steps. A measurement of a plurality of antenna configurations corresponding to each of the one or more user equipments is controlled to obtain a plurality of performance values. The performance values of the antenna configurations corresponding to the one or more user equipments are recorded. 
     According to another embodiment, a communication system is provided. The communication system is used for one or more user equipments. The communication system includes a plurality of Remote Radio Heads (RRHs) and a coordinator. Each of the RRHs is electrically connected to a plurality of antennas. The coordinator includes a performance measuring unit and a storing unit. The performance measuring unit is used for controlling a measurement of a plurality of antenna configurations corresponding to the one or more user equipments to obtain a plurality of performance values. The storing unit is used for recording the performance values of the antenna configurations corresponding to the one or more user equipments. 
     According to an alternative embodiment, a coordinator is provided. The coordinator is used for coordinating a communication system which is used for one or more user equipments. The communication system includes a plurality of Remote Radio Heads (RRHs). Each of the RRHs is electrically connected to a plurality of antennas. The coordinator includes a performance measuring unit and a storing unit. The performance measuring unit is used for controlling a measurement of a plurality of antenna configurations corresponding to the one or more user equipments to obtain a plurality of performance values. The storing unit is used for recording the performance values of the antenna configurations corresponding to the one or more user equipments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a communication system according to one embodiment 
         FIG. 2  shows a block diagram of the communication system. 
         FIG. 3  shows a flowchart of a measuring method of a plurality of antenna configurations according to one embodiment. 
         FIG. 4  shows a flowchart of an allocating method of the antenna configurations according to one embodiment. 
         FIGS. 5A to 5B  show a flowchart of another measuring method of the antenna configurations according to another embodiment. 
         FIG. 6  shows a flowchart of another allocating method of the antenna configurations according to another embodiment. 
         FIG. 7  shows another allocating method of the antenna configurations according to another embodiment. 
     
    
    
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1  which shows a communication system  1000  according to one embodiment. The communication system  1000  including a plurality of Remote Radio Heads (RRHs)  300  and a coordinator  500  serves for one or more user equipment(s)  100 . Each of the RRHs  300  is electrically connected to a plurality of antennas  310  (shown in  FIG. 2 ), each of which is a directional antenna. Each of the RRHs  300  adopts the smart antenna technology to dispose more than one antennas  310  at a board or a pillar. The antennas  310  have different radiation directions. In  FIG. 1 , beams BM of the antennas  310  are respectively shown. One or more antennas  310  connected to each of the RRHs  300  can be selected to form an antenna configuration. Please refer to table I, which illustrates a plurality antenna configurations formed by four RRHs  300  each of which is connected to three antennas  310 . The antenna configuration formed by the first antenna  310  of the first RRH  300 , the first antenna  310  of the second RRH  300 , the second antenna  310  of the third RRH  300  and the first antenna  310  of the fourth RRH  300  is recorded as “(100,100,010,100).” The antenna configuration formed by the first antenna  310  and the second antenna  310  of the first RRH  300 , the first antenna  310  and the third antenna  310  of the second RRH  300 , the second antenna  310  and the third antenna of the third RRH  300 , and the first to third antennas  310  of the fourth RRH  300  is recorded as “(110,101,011,111).” That is to say, in this example, (2 3 −1)*(2 3 −1)*(2 3 −1)*(2 3 −1), i.e.  2401 , kinds of antenna configurations can be formed. The communication system  1000  serves the user equipments  100  via the antenna configurations. 
     
       
         
           
               
               
               
               
             
               
                 TABLE I 
               
             
            
               
                   
               
               
                 First RRH 300 
                 Second RRH 300 
                 Third RRH 300 
                 Fourth RRH 300 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1st  
                 2nd  
                 3th  
                 1st  
                 2nd  
                 3th  
                 1st  
                 2nd  
                 3th  
                 1st  
                 2nd  
                 3th  
               
               
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
                 antenna 
               
               
                   
               
               
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
               
               
                 0 
                 1 
                 0 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
               
            
           
           
               
            
               
                 .  .  . 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 1 
                 1 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
               
               
                 1 
                 1 
                 1 
                 0 
                 1 
                 0 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
               
            
           
           
               
            
               
                 . . . 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 0 
                 0 
                 1 
                 0 
                 0 
               
            
           
           
               
            
               
                 . . . 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 0 
                 0 
               
            
           
           
               
            
               
                 . . . 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                   
               
            
           
         
       
     
     Please refer to  FIG. 2 , which shows a block diagram of the communication system  100 . As shown in  FIG. 2 , each of the RRHs  300  includes a switching unit  320  and is electrically connected to or includes several antennas  310 . The switching unit  320  is used for switching the antennas  310 . For example, the switching unit  320  may be a circuit board, a chip, a mechanical component, or a firmware (or a computer program) having controlling codes which controls the switching with the RF module. The coordinator  500  includes a base bend processing unit  510 , a performance measuring unit  520 , a storing unit  530  and an allocating unit  540 . The base bend processing unit  510  is used for processing signal, such as the analog to digital conversion, the signal decoding, the channel estimation, the Carrier Frequency Offset Estimation (CFO Estimation), or the Sampling Frequency Offset Estimation (SFO Estimation). 
     The performance measuring unit  520  is used for controlling the measurement of the antennas  310 . The performance measuring unit  520  may indicate the performance via the Channel Quality Indicator (CQI), Signal-to-Interference-plus-Noise Ratio (SINR), the Signal-to-Noise Ratio (SNR), the Received Signal Strength Indicator (RSSI), the Reference Signal Received Quality (RSRQ), the Reference Signal Received Power (RSRP) or the Throughput. The storing unit  530  is used for storing various data. For example, the storing unit  530  may be a memory, a hard disk or a storage unit in a cloud data center. The allocating unit  540  is used for allocating the antenna configurations. For example, the performance measuring unit  520  and the allocating unit  540  may be a circuit, a chip, a circuit board a firmware or a non-transitory computer readable medium. 
     The communication system  1000  of the present embodiment can measure and allocate the antenna configurations of the antennas  310  connected to the RRHs  300 , such that the signal strength and the signal coverage can be improved and is applicable to be used in the  5 G communication system. The measurement of the antenna configurations and the allocation of the antenna configurations are illustrated via several flowcharts. 
     Please refer to  FIG. 3 , which shows a flowchart of a measuring method of the antenna configurations according to one embodiment. In step S 101 , the performance measuring unit  520  sets a user equipment pool, and randomly selects one of the antenna configurations. The user equipment pool contains all of the user equipments  100  needed to be measured. 
     The performance measuring unit  520  selects one user equipment  100  from the user equipment pool (step S 102 ). And, the performance measuring unit  520  controls the measurement of the antenna configuration for this user equipment  100  (step S 103 ). 
     In step S 104 , after the performance measuring unit  520  obtains the performance value of the antenna configuration, this user equipment  100  is removed from the user equipment pool. For example, the performance value may be measured by the performance measuring unit  520 , or received from this user equipment  100 . 
     In step S 105 , the performance measuring unit  520  records the performance value in a performance table TB, and stores the performance table TB in the storing unit  530 . An embodiment, in the performance table TB, for each of the user equipment  100 , may records only the best N performance values. N is larger than or equal to 1. For example, please refer to table II, which illustrates the performance table TB of one user equipment  100 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE II 
               
               
                   
                   
               
               
                   
                 antenna 
                 performance 
               
               
                   
                 configuration 
                 value 
               
               
                   
                   
               
             
            
               
                   
                 (100,100,010,100) 
                 90 
               
               
                   
                 (010,100,010,010) 
                 75 
               
               
                   
                 (010,100,010,001) 
                 25 
               
               
                   
                 (010,010,010,100) 
                 10 
               
               
                   
                 (001,010,010,010) 
                 85 
               
               
                   
                   
               
            
           
         
       
     
     In step S 106 , the performance measuring unit  520  determines whether the user equipment pool is empty or not. If the user equipment pool is not empty, there is another user equipment  100  needed to be measured and the process returns to the steps S 102  to S 105  to obtain another performance table TB similar to the table II. When the user equipment pool is empty, all of the user equipments  100  are measured. The steps S 101  to S 106  are repeatedly performed until the number of the antenna configurations measured for the user equipments  100  reaches a predetermined number. 
     According to the measuring method of the antenna configurations, for each of the user equipments  100 , the performance values of the antenna configurations can be measured. The performance values of the antenna configurations for the user equipments  100  can be recorded. Please refer to table III, the performance values measured for the user equipments  100  can be integrated into one performance table TB. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE III 
               
             
            
               
                   
                   
               
               
                   
                 antenna 
                 user equipment 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 configuration 
                 A 
                 B 
                 C 
                 D 
                 E 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 (100,100,010,100) 
                 90 
                 70 
                 50 
                 30 
                 90 
               
               
                   
                 (010,100,010,010) 
                 75 
                 85 
                 70 
                 40 
                 75 
               
               
                   
                 (010,100,010,001) 
                 25 
                 80 
                 95 
                 75 
                 20 
               
               
                   
                 (010,010,010,100) 
                 10 
                 50 
                 70 
                 80 
                 10 
               
               
                   
                 (001,010,010,010) 
                 85 
                 65 
                 45 
                 25 
                 85 
               
               
                   
                 (001,001,010,001) 
                 20 
                 75 
                 90 
                 80 
                 15 
               
               
                   
                 (001,010,010,001) 
                 5 
                 45 
                 65 
                 75 
                 5 
               
               
                   
                 (001,100,010,001) 
                 80 
                 60 
                 40 
                 20 
                 80 
               
               
                   
                   
               
            
           
         
       
     
     After obtaining the performance values of the antenna configurations, the antenna configurations can be allocated to the user equipments  100 . Please refer to  FIG. 4 , which shows a flowchart of an allocating method of the antenna configurations according to one embodiment. In step S 201 , the allocating unit  540  sorts all of the user equipments  100 . 
     Then, in step S 202 , the allocating unit  540  selects one user equipment  100  having the highest priority form the user equipment pool. For example, the user equipment  100  labeled as “A” has the highest priority. 
     Then, in step S 203 , the best antenna configuration is selected from the performance table TB and is allocated to this user equipment  100 . For example, the antenna configuration which is “(100,100,010,100)” is allocated to the user equipment  100  labeled as “A.” And, the user equipment  100  labeled as “A” is removed from the user equipment pool. 
     In step S 204 , the allocating unit  540  determines whether the user equipment pool is empty or not. When the user equipment pool is empty, all of the user equipments  100  are allocated. 
     The allocating method of the antenna configurations described above may be performed repeatedly, until all of the user equipments  100  are allocated sequentially. According to the allocating method of the antenna configurations, the antenna configurations can be appropriately allocated to the user equipments  100  according to the performance values. If one antenna configuration is allocated to more than one user equipments  100 , then the user equipments  100  can use this antenna configuration in a time-divided manner or prevent from interference. 
     The measuring method of the antenna configuration according to one embodiment and the allocating method of the antenna configuration according to one embodiment have been disclosed above. However, the measuring method of the antenna configuration and the allocating method of the antenna configuration may be performed in other ways. In another embodiment, a region distribution technology may be used to reduce the number of measurements in the measuring method. Please refer to  FIGS. 5A to 5B , which show a flowchart of another measuring method of the antenna configuration according to another embodiment.  FIGS. 5A to 5B  are illustrated with the block diagram of  FIG. 2 . In step S 301 , for each of the user equipments  100 , the performance measuring unit  520  decides a serving RRH  300  from the RRHs  300 . The serving RRH may be the RRH  300  which is closest to this user equipment  100 , or the RRH  300  which has the strongest signal received from this user equipment  100 . 
     In step S 302 , the performance measuring unit  520  selects one user equipment  100  from the user equipment pool. 
     In step S 303 , the performance measuring unit  520  randomly selects one antenna  310  which is electrically connected to the serving RRH  300 . 
     In the step S 304 , the performance measuring unit  520  controls the measurement of the selected antenna  310  for this user equipment  100 . 
     In step S 305 , the performance measuring unit  520  obtains the performance value. For example, the performance value may be measured by the performance measuring unit  520 , or received from this user equipment  100  via the selected antenna  310 . 
     In step S 306 , the performance measuring unit  520  decides and records a serving antenna electrically connected to the serving RRH  300  which is the best antenna. 
     In S 307 , the performance measuring unit  520  determines whether there is any unmeasured antenna  310  electrically connected to the serving RRH  300 . If there is any unmeasured antenna  310 , the steps S 303  to S 306  are repeated performed, until the serving antenna  310  is decided. 
     In step S 308 , the performance measuring unit  520  removes this user equipment  100  from the user equipment pool. 
     Then, in step S 309 , the performance measuring unit  520  determines whether the user equipment pool is empty or not. If the user equipment pool is not empty, there are other user equipments needed to be measured and the process returns to the steps S 302  to S 308 , to decide the serving RRH  300  and the serving antenna  310  for each of the user equipments  100 . 
     In step S 310 , the performance measuring unit  520  initializes the user equipment pool. 
     Then, in step S 311 , the performance measuring unit  520  selects one user equipment  100  from the user equipment pool. 
     In the step S 312 , for this user equipment, the performance measuring unit  520  selects some of the antenna configurations including the serving antenna  310  electrically connected to the serving RRH  300 . 
     In step S 313 , the performance measuring unit  520  controls the measurement of the antenna configuration for this user equipment  100 . 
     In step S 314 , the performance measuring unit  520  obtains the performance value of the antenna configuration. For example, the performance value may be measured by the performance measuring unit  520 , or received from this user equipment  100  via the antenna configuration. 
     Then, in step S 315 , the performance measuring unit  520  records the performance values in the performance table TB, and stores the performance table TB in the storing unit  530 . In the performance table TB, for the each of the user equipments  100 , the best N performance values may be recorded. N is larger than or equal to 1. For example, please refer to table IV, which illustrates the performance table TB of one user equipment  100 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE IV 
               
               
                   
                   
               
               
                   
                 Antenna 
                 performance 
               
               
                   
                 configuration 
                 value 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 (100,100,010,100) 
                 90 
               
               
                   
                 (100,100,010,010) 
                 70 
               
               
                   
                 (100,100,010,001) 
                 20 
               
               
                   
                 (100,010,010,100) 
                 5 
               
               
                   
                 (100,010,010,010) 
                 80 
               
               
                   
                   
               
            
           
         
       
     
     In step S 316 , the performance measuring unit  520  removes this user equipment  100  from the user equipment pool. 
     Afterwards, in step S 317 , the performance measuring unit  520  determines whether the user equipment pool is empty or not. If the user equipment pool is not empty, there is another user equipment  100  needed to be measured and the process returns to the steps S 311  to S 316  to obtain another performance table TB similar to the table IV. When the user equipment pool is empty, all of the user equipments  100  are measured. 
     That is to say, after deciding the serving antenna  310  connected to the serving RRH  300  in the steps S 301  to S 309 , only the combinations of the serving antenna  310  and other antenna  310  are needed to be measured, the number of the measurement is greatly reduced. 
     Moreover, in another embodiment, an averaging algorithm can be used in the allocating method to reduce the antenna switch frequency of the antenna configurations. Please refer to  FIG. 6 , which shows a flowchart of another allocating method of the antenna configurations according to another embodiment. In step S 401 , the allocating unit  540  calculates the performance average of the performance values corresponding to the user equipments  100  for each of the antenna configurations. For example, the performance averages corresponding to the user equipments labeled “A” to “E” for the antenna configurations are illustrated in table V. 
     
       
         
           
               
               
               
               
             
               
                 TABLE V 
               
             
            
               
                   
               
               
                 antenna 
                 user equipment 
                 performance 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 configuration 
                 A 
                 B 
                 C 
                 D 
                 E 
                 average 
                 rank 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 (100, 100, 010, 100) 
                 90 
                 70 
                 50 
                 30 
                 90 
                 66 
                 2 
               
               
                 (010, 100, 010, 010) 
                 75 
                 85 
                 70 
                 40 
                 75 
                 69 
                 1 
               
               
                 (010, 100, 010, 001) 
                 25 
                 80 
                 95 
                 75 
                 20 
                 59 
                 4 
               
               
                 (010, 010, 010, 100) 
                 10 
                 50 
                 70 
                 80 
                 10 
                 44 
                 7 
               
               
                 (001, 010, 010, 010) 
                 85 
                 65 
                 45 
                 25 
                 85 
                 61 
                 3 
               
               
                 (001, 001, 010, 001) 
                 20 
                 75 
                 90 
                 80 
                 15 
                 59 
                 4 
               
               
                 (001, 010, 010, 001) 
                 5 
                 45 
                 65 
                 75 
                 5 
                 39 
                 8 
               
               
                 (001, 100, 010, 001) 
                 80 
                 60 
                 40 
                 20 
                 80 
                 56 
                 6 
               
               
                   
               
            
           
         
       
     
     In step S 402 , the allocating unit  540  sorts the antenna configurations. 
     Then, in step S 403 , the allocating unit  540  allocates the best antenna configuration, such as “(010,100,010,010)”, to the user equipments  100  labeled “A” to “E”. 
     Therefore, by performing this allocating method of the antenna configurations, the antenna configuration having the best performance value can be allocated to all of the user equipments  100 , such that the allocated antenna configuration is not needed to be switched often. 
     Furthermore, in another embodiment, a grouping technology can be used in the allocating method of the antenna configuration to achieve the advantages of  FIGS. 4 and 6 . Please refer to  FIG. 7 , which shows another allocating method of the antenna configurations according to another embodiment. In step S 501 , the allocating unit  540  classifies the user equipments  100  into a plurality of groups. For example, the user equipments  100  correspond to the same serving RRH  300  may be classified into the same group. Or, the user equipments  100  located closely may be classified into the same group. 
     In the step S 502 , the allocating unit  540  calculates the performance average of the performance values of each of the antenna configurations corresponding to the user equipments  100  in each of the groups. For example, the performance averages corresponding to the user equipments  100  in difference groups are illustrated in table VI. 
     
       
         
           
               
               
               
             
               
                 TABLE VI 
               
             
            
               
                   
               
               
                   
                 group 
                 group 
               
            
           
           
               
               
               
               
               
            
               
                   
                 user 
                 perfor- 
                 user 
                 perfor- 
               
               
                 antenna 
                 equipment 
                 mance 
                 equipment 
                 mance 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 configuration 
                 A 
                 C 
                 average 
                 B 
                 D 
                 E 
                 average 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 (100, 100, 010, 100) 
                 90 
                 50 
                 70 
                 70 
                 30 
                 90 
                 63 
               
               
                 (010, 100, 010, 010) 
                 75 
                 70 
                 73 
                 85 
                 40 
                 75 
                 67 
               
               
                 (010, 100, 010, 001) 
                 25 
                 95 
                 60 
                 80 
                 75 
                 20 
                 58 
               
               
                 (010, 010, 010, 100) 
                 10 
                 70 
                 40 
                 50 
                 80 
                 10 
                 47 
               
               
                 (001, 010, 010, 010) 
                 85 
                 45 
                 65 
                 65 
                 25 
                 85 
                 58 
               
               
                 (001, 001, 010, 001) 
                 20 
                 90 
                 55 
                 75 
                 80 
                 15 
                 57 
               
               
                 (001, 010, 010, 001) 
                 5 
                 65 
                 35 
                 45 
                 75 
                 5 
                 42 
               
               
                 (001, 100, 010, 001) 
                 80 
                 40 
                 60 
                 60 
                 20 
                 80 
                 53 
               
               
                   
               
            
           
         
       
     
     In step S 503 , the allocating unit  540  selects one group from a group pool. 
     Then, in step S 504 , the allocating unit  540  allocates the best antenna configuration to all of the user equipments  100  in this group. After allocating, the allocating unit  540  removes this group from the group pool. For example, in the group including the user equipments  100  labeled “A” and “C”, the best antenna configuration is “(010,100,010,010)”, so this antenna configuration is allocated to the user equipments labeled “A” and “C.” 
     In step S 505 , the allocating unit  540  determines whether the group pool is empty or not. If the group pool is not empty, there is another group needed to be allocated and the process returns to steps S 503  to S 504  for allocating the another group. When the group pool is empty, all of the user equipments  100  in all of the groups are allocated. 
     By performing the allocating method of the antenna configurations, the antenna configuration can be appropriately allocated to the user equipments  100  according to the performance values. If one antenna configuration is allocated to more than one user equipments  100 , then the user equipments  100  can use this antenna configuration in a time-divided manner for prevent from interference. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.