Method and arrangement in a radio communication system

Abstract

The present invention concerns a process in a radio communication system which is arranged for packet data transmission according to a message-synchronized ALOHA protocol with reservation. Mobile stations in the system are arranged to send access requests to a base station during a reservation phase in a mobile radio system which uses this protocol. The base station is arranged to receive and comply with the access request from a first mobile station by sending thereto a channel reservation message ( 2 ) comprising a channel reservation ( 3 ). The base station is further arranged to receive access requests from at least a second mobile station for which channel reservation momentarily cannot be carried out. According to the process of the invention an access request received from the second mobile station is confirmed when channel reservation cannot be carried out in the usual manner. The confirmation is sent in the form of an access confirmation ( 4, 5 ) which is included in the same channel reservation message ( 2 ) as the channel reservation ( 3 ) for the first mobile station.

1. In a radio communication system which is arranged for packet data transmission via at least one time-divided channel between a base station and mobile stations, according to a message-synchronized ALOHA protocol with reservation, the mobile stations being arranged to send access requests to the base station, which is arranged to receive and comply with access requests from at least a first mobile station by sending thereto a channel reservation message comprising a channel reservation, whereby time slots are reserved for packet data transmission between the first mobile station and the base station, and to receive access requests from a first group of mobile stations for which channel reservation momentarily cannot be carried out, a method comprising the steps of:
 confirming the reception of access requests from the first group of mobile stations in the form of an access confirmation from the base station to each of the mobile stations included in the first group;  
 including the access confirmations in the channel reservation message with the channel reservation to the first mobile station;  
 arranging the first group in the radio communication system associated with the access confirmations in a queue, a queue position being allocated to each of the mobile stations in this group; and  
 carrying out channel reservation for the mobile stations according to their queue positions.  
 
     
     
       2. A method according to  claim 1 , further comprising the steps of:
 reading the channel reservation message by all the mobile stations from which access requests are received in the base station; and  
 including access confirmations in the channel reservation message received in the mobile stations, whereby the latter are actuated so as to await channel reservation without making repeated access requests.  
 
     
     
       3. A method according to  claim 1 , further comprising the steps of:
 supplying a first reference in the channel reservation to the first mobile station, which first reference refers to a first time slot in the time-divided channel, in which first time slot the access request from the first mobile station was received in the base station; and  
 supplying a second reference in each access confirmation, which second reference refers to a second time slot in the time-divided channel, in which second time slot access requests were received in the base station from the respective mobile station for which the access confirmations are intended.  
 
     
     
       4. A method according to  claim 3 , wherein:
 the second reference is made up of the number of time slots between the first time slot and the second time slot.  
 
     
     
       5. In a radio communication system which is arranged for packet data transmission, via at least one time-divided channel, between a base station and mobile stations, according to a message-synchronized ALOHA protocol with reservation, a method comprising the following steps:
 receiving access requests from the mobile stations;  
 complying with the access request from at least a first mobile station by sending a channel reservation thereto, whereby time slots are reserved for packet data transmission between the first mobile station and the base station;  
 giving access confirmations to each mobile station in a first group of mobile stations on receipt of access requests from the first group of mobile stations for which channel reservation momentarily cannot be carried out;  
 sending these access confirmations in the same message as the channel reservation for the first mobile station;  
 arranging, in association with the access confirmations, in the radio communication system a queue of the mobile stations in the first group, a queue position being allocated to each mobile station; and  
 carrying out channel reservation for the mobile stations according to their queue positions.  
 
     
     
       6. In a radio communication system, which is arranged for packet data transmission via at least one time-divided channel between a base station and mobile stations, according to a message-synchronized ALOHA protocol with reservation, the mobile station (MS 1 -MS 3 ) being arranged to send access requests to the base station, the base station comprising:
 means for receiving and complying with access requests from at least a first mobile station by sending thereto a channel reservation message comprising a channel reservation, whereby a number of time slots are reserved for packet data transmission between the first mobile station and the base station;  
 means for receiving access requests from a first group of mobile stations for which channel reservation momentarily cannot be carried out;  
 means for giving access confirmations to each of the mobile stations which are included in the first group and from which access requests have been received;  
 means for including said access confirmations in the same channel reservation message as said channel reservation for the first mobile station;  
 means for arranging a queue of the mobile stations in the first group, a queue position being allocated to each mobile station; and  
 means for carrying out channel reservation for the mobile stations in the first group according to their queue positions.  
 
     
     
       7. In a radio communication system, which is arranged for packet data transmission via at least one time-divided channel between a base station and mobile stations, a mobile station comprising:
 means for sending an access request to the base station;  
 means for reading each channel reservation message in the time-divided channel; and  
 means for receiving an access confirmation in said channel reservation message when the channel reservation does not concern this mobile station, whereupon the mobile station is actuated to await channel reservation without further access requests being sent.  
 
     
     
       8. A method for a mobile station to communicate with a base station in a radio communication system, comprising the steps of:
   sending an access request from the mobile station to the base station;        monitoring, by the requesting mobile station, for a response to the access request from the base station;        receiving as the response, by the requesting mobile station, an access confirmation that does not include a channel reservation for the requesting mobile station; and        in response to receiving the access confirmation, suppressing further access requests by the requesting mobile station while awaiting the channel reservation from the base station.     
     
     
       9. A mobile station comprising:
   means for sending an access request to a base station;        means for monitoring, by the mobile station, for a response to the access request from the base station; and        means for receiving as the response, by the mobile station, an access confirmation that does not include a channel reservation for the mobile station, whereupon the mobile station is adapted to await the channel reservation without sending further access requests to the base station.     
     
     
       10. A method for a base station to assign a communication channel to a mobile station in a radio communication system, comprising the steps of:
   receiving an access request from said mobile station;        determining whether a communication channel is available for the requesting mobile station;        upon determining that a communication channel is available, transmitting a channel reservation to the requesting mobile station; and        upon determining that a communication channel is not available:      transmitting to the requesting mobile station, an access confirmation that does not include a channel reservation for the requesting mobile station, whereupon the requesting mobile station awaits the channel reservation without transmitting subsequent access requests; and        transmitting the channel reservation to the requesting mobile station when a communication channel becomes available.       
     
     
       11. A base station in a radio communication system, comprising:
   means for receiving an access request from a mobile station;        means for determining whether a communication channel is available for the requesting mobile station;        means, responsive to a determination that a communication channel is available, for transmitting to the requesting mobile station, a channel reservation; and        means, responsive to a determination that a communication channel is not available, for transmitting to the requesting mobile station, an access confirmation that does not include a channel reservation for the requesting mobile station, whereupon the requesting mobile station awaits the channel reservation without transmitting subsequent access requests.     
     
     
       12. In a radio communication system which is arranged for packet data transmission via at least one time- divided channel between a base station and mobile stations, according to a message - synchronized ALOHA protocol with reservation, the mobile stations being arranged to send access requests to the base station, which is arranged to receive and comply with access requests from at least a first mobile station by sending thereto a channel reservation message comprising a channel reservation, whereby time slots are reserved for packet data transmission between the first mobile station and the base station, and to receive access requests from a first group of mobile stations for which channel reservation momentarily cannot be carried out, a method comprising the steps of:      scheduling the transmission of an access request, the scheduling by a first mobile station timed to reduce simultaneous access requests from a plurality of mobile stations, the access request comprising the first mobile station's desired resources;        confirming the reception of the access request from the first mobile station in the form of a channel reservation;        confirming the reception of access requests from the first group of mobile stations in the form of an access confirmation from the base station to each of the mobile stations included in the first group, wherein the access confirmation is in the channel reservation to the first mobile station;        queuing the first group in the radio communication system associated with the access confirmations, a queue position being allocated to each of the mobile stations in this group;        idling the first group of mobile stations, the idling responsive to the queuing; and        carrying out channel reservation for the mobile stations according to their queue positions.     
     
     
       13. The method of  claim 12 , wherein the first group of mobile stations remains idle for a predetermined timed duration. 
     
     
       14. The method of  claim 12 , wherein the first group of mobile stations remains idle until a prompt is received by the base station. 
     
     
       15. In a radio communication system, which is arranged for packet data transmission via at least one time- divided channel between a base station and mobile stations, a mobile station comprising:      means for sending an access request to the base station, the access request scheduled to reduce simultaneous access requests from a plurality of mobile stations, the access request comprising the first mobile station's desired resources;        means for monitoring for a transmission from the base station; and        means for receiving an access confirmation from the base station, wherein the access confirmation idles the mobile station to await channel reservation without further access requests being sent.