Communication system, communication device, communication terminal, and communi- cation method

Abstract

According to a communications method according to the present invention, data is transmitted from a base station to two or more terminals via a common channel, and transmission power, with which the data is transmitted from the base station to the two or more terminals, is controlled according to a reception state of at least one of the two or more terminals. Furthermore, the terminal transmits reception capability information at a time of selection combining, and at least one of the two or more base stations receives the reception capability information at the time of selective combining and notifies the reception capability information to a radio network controller (RNC) which controls the two or more base stations. When a connection request is issued to the terminal, the RNC refuses assignment of a dedicated channel to the connection request when determining that the assignment of the dedicated channel to the terminal cannot be done based on the reception capability information at the time of selective combining.

1 . An MBMS (Multimedia Broad Cast Multicast Service) communications system having a Radio Network Controller (RNC) for controlling two or more base stations, each of the two or more base stations carrying out transmission power control according to a reception state of a terminal existing in a cell thereof and the two or more base stations broadcasting or multicasting data having identical contents to two or more terminals, wherein 
 each of the two or more base stations includes a first transmitting means for transmitting data using a dedicated channel and for transmitting MBMS data using a common channel; and a first receiving means for receiving reception capability information at a time of selective combining for the common channel from the terminal, wherein    each of the two or more terminals includes a second receiving means disposed for receiving data via the dedicated channel, and for receiving the MBMS data from each of the two or more base stations via the common channel at a time of reception of the MBMS data;    a selective combining means for selecting MBMS data showing a correct received result from among plural MBMS data which the second receiving means has received from the two or more base stations; and    a second transmitting means for transmitting reception capability information about reception capability of the second receiving means at the time of selective combining, and wherein    the radio network controller (RNC) includes a control means for, when a connection request is issued to the terminal which is receiving the MBMS data, determining whether or not to assign the dedicated channel to the terminal based on the reception capability information at the time of selective combining which the base stations has received, and for refusing assignment of the dedicated channel to the connection request when determining that the assignment is impossible.    
   
   
       2 . The communications system according to  claim 1 , wherein the second receiving means has two or more receiving units disposed respectively for two or more common channels, for receiving the MBMS data from the base stations, and at least one receiving unit of the two or more receiving units receives data selectively via the common channel or the dedicated channel.  
   
   
       3 . The communications system according to  claim 1 , wherein the reception capability information is information indicating whether or not it is possible to receive data via the dedicated channel at the time of selective combining.  
   
   
       4 . The communications system according to  claim 1 , wherein the reception capability information is information about a number of common channels via which data can be received at the time of selective combining.  
   
   
       5 . The communications system according to  claim 4 , wherein when a connection request is issued to the terminal which is carrying out selective combining, the RNC determines whether or not to refuse the connection request based on a difference between the number of common channels via which data can be received at the time of selective combining, and a number of common channels which the terminal uses actually for the selective combining.  
   
   
       6 . The communications system according to  claim 1 , wherein when a connection request is issued to the terminal which is carrying out selective combining, the RNC determines whether or not to refuse the connection request based on a communication speed of the dedicated channel which is to be used for the connection request.  
   
   
       7 . The communications system according to  claim 1 , wherein the reception capability information further includes information indicating a priority of the selective combining to reception of the dedicated channel.  
   
   
       8 . The communications system according to  claim 6 , wherein when a connection request is issued to the terminal which is carrying out selective combining, the RNC determines whether or not to refuse the connection request based on the information indicating a priority of the selective combining to reception of the dedicated channel.  
   
   
       9 . A communications apparatus for use in an MBMS (Multimedia Broad Cast Multicast Service) communications system which carries out transmission power control according to a reception state of a terminal existing in a cell thereof and which broadcasts or multicasts data having identical contents from two or more transmitting points to two or more terminals, the communications apparatus comprising: 
 a transmitting means for transmitting data using a dedicated channel and for transmitting MBMS data using a common channel;    a receiving means for receiving reception capability information at a time of selective combining for the common channel from the terminal; and    a control means for, when a connection request is issued to the terminal which is receiving the MBMS data, determining whether or not to assign the dedicated channel to the terminal based on the reception capability information at the time of selective combining which the receiving means has received, and for refusing assignment of the dedicated channel to the connection request when determining that the assignment is impossible.    
   
   
       10 . A terminal for use in an MBMS (Multimedia Broad Cast Multicast Service) communications system which broadcasts or multicasts data having identical contents from two or more base stations to two or more terminals, the terminal comprising: 
 a receiving means disposed for receiving data via a dedicated channel, and for receiving MBMS data from each of the two or more base stations via a common channel at a time of reception of the MBMS data;    a selective combining means for selecting MBMS data showing a correct received result from among plural MBMS data which the receiving means has received from the two or more base stations; and    a transmitting means for transmitting reception capability information about reception capability of the receiving means at a time of selective combining.    
   
   
       11 . The terminal according to  claim 10 , wherein the transmitting means transmits, as the reception capability information, information indicating whether the receiving means can receive data via the dedicated channel at the time of selective combining.  
   
   
       12 . The terminal according to  claim 10 , wherein the transmitting means transmits, as the reception capability information, a number of channels which can be combined selectively at the time of selective combining to the base stations.  
   
   
       13 . The terminal according to  claim 10 , wherein the transmitting means transmits a number of common channels which are used for the selective combining to the base stations.  
   
   
       14 . The terminal according to  claim 10 , wherein the transmitting means transmits priority information indicating whether a higher priority is given to either reception of the common channel, or reception of the dedicated channel.  
   
   
       15 . The terminal according to  claim 14 , wherein when a request for connection via the dedicated channel is issued to the terminal, the receiving means reduces a number of common channels via which data is received for the selective combining according to the priority information, and starts reception of the dedicated channel.  
   
   
       16 . The terminal according to  claim 10 , wherein the transmitting means transmits a number of common channels which are used for the selective combining to the base stations.  
   
   
       17 . The terminal according to  claim 10 , wherein the terminal has a control means for observing signals from the base stations which the receiving means has received and for generating transmission power control information by which the terminal makes a request of the base stations to increase or decrease transmission power according to an observation result, and the transmitting means transmits the transmission power control information to the base stations.  
   
   
       18 . A time division multiple access (CDMA) communications method of transmitting data from a base station to two or more terminals via a common channel, and controlling transmission power, with which the data is transmitted from the base station to the two or more terminals, according to a reception state of at least one of the two or more terminals, the communications method comprising the steps of: 
 the terminal transmitting reception capability information at a time of selection combining;    at least one of the two or more base stations receiving the reception capability information at the time of selective combining, and notifying the reception capability information to a radio network controller (RNC) which controls the two or more base stations; and    when a connection request is issued to the terminal, the RNC refusing assignment of a dedicated channel to the connection request when determining that the assignment of the dedicated channel to the terminal cannot be done based on the reception capability information at the time of selective combining.    
   
   
       19 . A time division multiple access (CDMA) communications method of transmitting data from a base station to two or more terminals via a common channel, and controlling transmission power, with which the data is transmitted from the base station to the two or more terminals, according to a reception state of at least one of the two or more terminals, the communications method comprising the steps of: 
 the two or more base stations transmitting data to a common terminal;    receiving reception capability information at a time of selective combining from the common terminal, and notifying the reception capability information to a radio network controller (RNC) which controls the two or more base stations; and    when a connection request is issued to the terminal, the RNC refusing assignment of a dedicated channel to the connection request when determining that the assignment of the dedicated channel to the terminal cannot be done based on the reception capability information at the time of selective combining.    
   
   
       20 . A communications method for use in a time division multiple access (CDMA) terminal which receives common data from two or more base stations via a common channel, the communications method comprising the steps of: 
 receiving data from the two or more base stations via the common channel;    selecting data showing a correct received result from among data received from the two or more base stations based on received results of the data received from the two or more base stations; and    transmitting reception capability information at a time of selective combining to one of the two or more base stations which has transmitted the selected data.    
   
   
       21 . The communications method according to  claim 20 , wherein the method further comprises the step of the terminal transmitting a number of common channels which are used for the selective combining to the base station.