Cell station, radio communication system, communication control method of cell station, and method of building radio communication network

Abstract

Traffic that can be processed at a cell station is increased without reducing communication quality. When a channel is allocated to every time slot constituting a communication frame and radio control section receives a link channel establishment request from a personal station through a control channel allocated to any of the time slots, a control section notifies the personal station through the traffic channel of an allocation message indicating that the time slot allocated to the control channel will be allocated to a traffic channel. The transmission of the control channel is stopped when a predetermined time (a control channel transmission/reception duration) passes after the notification of the allocation message.

What is claimed is:  
     
         1 . A cell station accommodating a personal station by using a time division multiple access method, comprising: 
 communication unit which transmits and receives a frame including a plurality of time slots; and    control unit which allocates a traffic channel or a control channel to each of the time slots constituting the frame, wherein,    in the case that a channel is allocated to every time slot constituting the frame and the communication unit receives a link channel establishment request from the personal station through the control channel allocated to any of the time slots, the control unit notifies the personal station through the control channel that the time slot allocated to the control channel will be allocated to a traffic channel and stops transmission and reception of the control channel when a predetermined time passes after the notice.    
     
     
         2 . A cell station according to  claim 1 , wherein 
 the predetermined time is set such that it is longer than an estimated time until the reception of a link channel establishment re-request when the re-request is sent as a response of the personal station to the notice and is shorter than an estimated time until the reception of a synchronization burst signal when the signal is set as the response.    
     
     
         3 . A cell station accommodating a personal station by using a time division multiple access method, comprising: 
 communication unit which transmits and receives a frame including a plurality of time slots;    control unit which allocates a traffic channel or a control channel to each of the time slots constituting the frame; and    timing storing unit which stores timing for transmitting and receiving a frame including the control channel, wherein,    in the case that a traffic channel is allocated to every time slot constituting the frame, when any of the traffic channels is disconnected to make a time slot open, the control unit controls the communication unit such that the control channel is transmitted and received in the time slot which has become open in a frame transmitted at said timing.    
     
     
         4 . A cell station according to  claim 3 , wherein: 
 the control unit controls the communication unit to perform carrier sensing for the control channel in the time slot which has become open in the frame transmitted and received at said timing;    when no interference is detected, the control unit controls the communication unit to transmit and receive the control channel in the time slot which has become open in the frame transmitted and received at said timing; and    when interference is detected, the control unit controls the communication unit such that it repeats a process of switching a traffic channel allocated to another time slot to the time slot which has become open and performing carrier sensing for the control channel in the another time slot in a frame transmitted and received at timing stored in the timing storing unit until no interference is detected and it transmits and receives the control channel in a time slot in which no interference has been detected in the frame transmitted and received at said timing.    
     
     
         5 . A cell station accommodating a personal station by using a time division multiple access method, comprising: 
 communication unit which transmits and receives a frame including a plurality of time slots;    control unit which allocates a traffic channel or a control channel to each of the time slots constituting the frame; and    traffic monitoring unit which monitors communication traffic, wherein    the control unit performs carrier sensing for the control channel in a time slot to which the control channel is allocated according to results of the monitoring by the traffic monitoring unit and adjusts timing for transmitting and receiving a frame including the control channel.    
     
     
         6 . A cell station according to  claim 5 , wherein: 
 the traffic monitoring unit monitors the number of link channel establishment requests received from the personal station through the control channel within a predetermined time as the communication traffic; and    the control unit performs said adjustment when the communication traffic monitored by the traffic monitoring unit is equal to or smaller than a predetermined threshold.    
     
     
         7 . A cell station accommodating a personal station by using a time division multiple access method, comprising: 
 communication unit which transmits and receives a frame including a plurality of time slots;    control unit which allocates a traffic channel or a control channel to each of the time slots constituting the frame; and    traffic monitoring unit which monitors communication traffic, wherein:    the control unit operates in either of a first mode in which the control channel is always allocated to at least one of the time slots constituting the frame and a second mode in which a traffic channel can be allocated to every time slot constituting the frame; and    the operation modes are switched according to results of the monitoring by the traffic monitoring unit.    
     
     
         8 . A cell station according to  claim 7 , wherein: 
 the traffic monitoring unit monitors the number of rejections of link channel establishment requests received from the personal station through the control channel within a predetermined time as the communication traffic; and    the control unit switches the operation mode to the second mode when the communication traffic monitored by the traffic monitoring unit becomes equal to or greater than a predetermined threshold during an operation in the first mode.    
     
     
         9 . A radio communication system having a plurality of cell stations and a communication network connecting the plurality of cell stations, wherein 
 at least one of the plurality of cell stations is a cell station according to claims  1 .    
     
     
         10 . A communication control method for a cell station accommodating a personal station by using a time division multiple access method, wherein: 
 in the case that a channel is allocated to every time slot constituting the frame, when a link channel establishment request is received from the personal station through the control channel allocated to any of the time slots, the personal station is notified through the control channel that the time slot allocated to the control channel will be allocated to a traffic channel; and    transmission and reception of the control channel is stopped when a predetermined time passes after the notice.    
     
     
         11 . A communication control method for a cell station accommodating a personal station by using a time division multiple access method, wherein, 
 in the case that a traffic channel is allocated to every time slot constituting the frame, when any of the traffic channels is disconnected to make a time slot open, the control channel is transmitted and received in the time slot which has become open in a frame transmitted and received at timing stored in advance in storing unit.    
     
     
         12 . A communication control method for a cell station accommodating a personal station by using a time division multiple access method, comprising the steps of: 
 monitoring communication traffic; and    performing carrier sensing for a control channel in a time slot to which the control channel is allocated and adjusting timing for transmitting and receiving a frame including the control channel when results of the monitoring becomes equal to or greater than a predetermined threshold.    
     
     
         13 . A communication control method for a cell station accommodating a personal station by using a time division multiple access method, comprising the steps of: 
 monitoring communication traffic; and    switching the operation mode to a second mode in which a traffic channel can be allocated to every time slot constituting a frame when results of the monitoring becomes equal to or greater than a predetermined threshold during an operation in a first mode in which a control channel is always allocated to at least one of time slots constituting a frame to be transmitted and received.    
     
     
         14 . A method of constructing a radio communication network utilizing a plurality of cell stations connected to each other through a communication network, wherein 
 at least one of the plurality of cell stations carries out the communication control method for a cell station according to  claim 10 .    
     
     
         15 . A method of constructing a radio communication network utilizing a plurality of cell stations connected to each other through a communication network, wherein 
 at least one of the plurality of cell stations carries out the communication control method for a cell station according to  claim 11 .    
     
     
         16 . A method of constructing a radio communication network utilizing a plurality of cell stations connected to each other through a communication network, wherein 
 at least one of the plurality of cell stations carries out the communication control method for a cell station according to  claim 12 .    
     
     
         17 . A method of constructing a radio communication network utilizing a plurality of cell stations connected to each other through a communication network, wherein 
 at least one of the plurality of cell stations carries out the communication control method for a cell station according to  claim 13.