Preamble allocation method and random access method in mobile communication system

Abstract

The present invention relates to a A preamble allocation method and a random access method in a mobile communication system. In the present invention, includes allocating one among preamble resources is allocated to a specific mobile stations station in advance, before random access. The mobile stations request station requests random access by transmitting a preamble based on the pre-allocated preamble resource to a base station. It is therefore possible to prevent A collision caused by the fact that other mobile stations transmit the same preamble the same preamble transmission by another mobile station may be prevented.

The invention claimed is: 
     
       1. A communication method for a base station to allocate a preamble to a mobile station, comprising:
 classifying preamble resources into a contention-based group and a reserved allocation group to generate classification information for the preamble resources; 
 transmitting the classification information to the mobile station; 
 selecting one preamble index belonging to the a reserved allocation group; and 
 sending, to the a mobile station, the selected preamble index belonging to the reserved allocation group; 
 receiving, by a base station, a random access preamble from the mobile station, wherein the random access preamble is associated with an identifier, and the identifier is determined based on a frequency and a time through which the random access preamble is transmitted; 
 transmitting, by the base station, scheduling information to the mobile station through a control channel based on the identifier; and 
 transmitting, by the base station, a random access response to the mobile station through a shared channel for data transmission, wherein the scheduling information indicates at least a frequency and a time of the random access response at the shared channel for data transmission, 
 wherein the mobile station requests random access based on a corresponding preamble generated from the received selected preamble indexwherein the random access preamble received from the mobile station corresponds to the selected preamble index. 
 
     
     
       2. The method of  claim 1 , wherein sending the one preamble index comprises:
 sending, to the mobile station, the one preamble index via downlink data generating indication information.   
     
     
       3. The method of  claim 1 , wherein sending the one preamble index comprises:
 sending, to the mobile station, the one preamble index via a handover-related message.   
     
     
       4. The method of  claim 1 , further comprising:
 receiving a preamble corresponding to the one preamble index; and   transmitting a random access response message to the mobile station.   
     
     
       5. The method of claim  4  1, wherein the random access response message includes radio resource allocation information. 
     
     
       6. The method of  claim 5 , wherein the random access response message further includes information on the random access preamble transmitted by the mobile station. 
     
     
       7. The method of  claim 6 , wherein the random access response message further includes at least one of downlink resource allocation information, scheduling identifier, and information on whether the base station successfully received the preamble based on the one preamble index informed by the base station. 
     
     
       8. The method of  claim 1 , wherein a preamble consists of a first part representing a random property and a second part representing additional information,
 wherein classifying the preamble resources comprises:   classifying the preamble resources into the contention-based group, the reserved allocation group, and an additional information group.   
     
     
       9. The method of  claim 8 , wherein the additional information is one of the following:
 CQI (channel quality indicator) information representing whether a corresponding channel has greater quality than a predetermined value in a service area of the base station;   information representing that the mobile station accesses through a handover process from a neighboring base station; and   information representing that the mobile station does not perform initial access but maintains a connection with the base station.   
     
     
       10. A method for a base station to perform a random access procedure with a mobile station, comprising:
 classifying a plurality of random access preambles into a contention based random access preamble group and a non-contention based random access preamble group to generate system information including classification information which enables to classify the plurality of random access preambles;   broadcasting the system information;   selecting one random access preamble index corresponding to one random access preamble belonging to the non-contention based random access preamble group;   allocating, to the mobile station, the corresponding one random access preamble in association with the selected random access preamble index;   sending, to the mobile station the selected random access preamble index; and   in response to receiving, from the mobile station, a random access request on the basis of the corresponding one random access preamble generated from the selected random access preamble index:   providing a random access response to the mobile station.   
     
     
       11. The method of  claim 10 , wherein allocating the one random access preamble comprises:
 allocating, to the mobile station, the one random access preamble belonging to the non-contention based random access preamble group when downlink data is generated or the mobile station performs a handover.   
     
     
       12. The method of  claim 10 , further comprising:
 receiving the allocated random access preamble; and   transmitting a random access response to the mobile station.   
     
     
       13. The method of  claim 12 , wherein the random access response includes radio resource allocation information and information on the allocated random access preamble. 
     
     
       14. A method for a base station to perform a random access procedure with a mobile station, comprising:
 classifying a plurality of random access preambles into a contention based random access preamble group and a non-contention based random access preamble group to generate system information including classification information which enables to classify the plurality of random access preambles;   broadcasting the system information;   selecting one random access preamble index corresponding to one random access preamble belonging to the non-contention based random access preamble group;   allocating, to the mobile station, the corresponding one random access preamble in association with the selected random access preamble index;   sending, to the mobile station the selected random access preamble index; and   in response to receiving, from the mobile station, a random access request on the basis of the corresponding one random access preamble generated from the selected random access preamble index:   receiving the allocated random access preamble to provide a random access response to the mobile station.   
     
     
       15. A random access communication method of a mobile station, comprising:
 receiving, from a base station, system information including information which enables to classify a plurality of random access preambles into a contention based random access preamble group and a non-contention based random access preamble group; 
 receiving, from the a base station, a selected random access preamble index indicating allocation information for one corresponding to a random access preamble belonging to the a non-contention based random access preamble group; 
 when the mobile station receivesin response to receiving, from the base station, the selected random access preamble index, generating the corresponding random access preamble using the selected random access preamble index and;  
 transmitting a random access request including the corresponding, by a mobile station, the random access preamble to the base station, wherein the random access preamble is associated with an identifier, and the identifier is determined based on a frequency and a time through which the random access preamble is transmitted; 
 receiving, by the mobile station, scheduling information from the base station through a control channel based on the identifier; and 
 receiving, by the mobile station, a random access response from the base station through a shared channel for data transmission, wherein the scheduling information indicates at least a frequency and a time of the random access response at the shared channel for data transmission. 
 
     
     
       16. A random access method of  claim 15 , when the mobile station does not receive allocation information for one random access preamble belonging to the non-contention based random access preamble group, transmitting one random access preamble belonging to the contention based random access preamble group to the base station. 
     
     
       17. The method of  claim 15 , wherein receiving the selected random access preamble index includes receiving the selected random access preamble index via downlink data generating indication information. 
     
     
       18. The method of  claim 15 , wherein receiving the selected random access preamble index includes receiving the selected random access preamble index via a handover-related message. 
     
     
       19. A random access method of a mobile station, comprising:
 receiving, from a base station, system information including information which enables to classify a plurality of random access preambles into a contention based random access preamble group and a non-contention based random access preamble group;   receiving, from the base station, a selected random access preamble index indicating allocation information for one corresponding random preamble belonging to the non-contention based random access preamble group;   when the mobile station receives, from the base station, the selected random access preamble index, generating the corresponding random preamble using the selected random access preamble index and transmitting a random access request including the corresponding random access preamble to the base station;   when the mobile station does not receive random access preamble index indicating allocation information for random access preamble belonging to the non-contention based random access preamble group, transmitting a contention-based random access request including one random access preamble belonging to a contention based random access preamble group to the base station; and   receiving a random access response from the base station.   
     
     
       20. The method of  claim 19 , wherein receiving the selected random access preamble index includes receiving the selected random access preamble index via downlink data generating indication information. 
     
     
       21. The method of  claim 19 , wherein receiving the selected random access preamble index includes receiving the selected random access preamble index via a handover related message. 
     
     
       22. The method of claim 15, wherein the random access response includes radio resource allocation information. 
     
     
       23. The method of claim 22, wherein the random access response further includes information on the random access preamble transmitted by the mobile station. 
     
     
       24. A communication device, comprising:
 a circuitry configured to:
 select one preamble index belonging to a reserved allocation group; 
 cause the communication device to send, to a mobile station, the selected preamble index belonging to the reserved allocation group; 
 cause the communication device to receive, from the mobile station, a random access preamble, wherein the random access preamble is associated with an identifier, and the identifier is determined based on a frequency and a time through which the random access preamble is transmitted; 
 cause the communication device to transmit scheduling information to the mobile station through a control channel based on the identifier; and 
 cause the communication device to transmit a random access response to the mobile station through a shared channel for data transmission, wherein the scheduling information indicates at least a frequency and a time of the random access response at the shared channel for data transmission, 
 wherein the random access preamble received from the mobile station corresponds to the selected preamble index. 
   
     
     
       25. The communication device of claim 24, wherein the random access response includes radio resource allocation information. 
     
     
       26. A terminal, comprising:
 a circuitry configured to:
 cause the terminal to receive, from a base station, a random access preamble index corresponding to a random access preamble belonging to a non-contention based random access preamble group; 
 cause the terminal to generate, in response to receiving from the base station the random access preamble index, the corresponding random access preamble using the random access preamble index; 
 cause the terminal to transmit the random access preamble to the base station, wherein the random access preamble is associated with an identifier, and the identifier is determined based on a frequency and a time through which the random access preamble is transmitted; 
 cause the terminal to receive scheduling information from the base station through a control channel based on the identifier; and 
 cause the terminal to receive a random access response from the base station through a shared channel for data transmission, wherein the scheduling information indicates at least a frequency and a time of the random access response at the shared channel for data transmission. 
   
     
     
       27. The terminal of claim 26, wherein the random access response includes radio resource allocation information. 
     
     
       28. The terminal of claim 27, wherein the random access response further includes information on the random access preamble transmitted by the terminal. 
     
     
       29. A communication device for a terminal, the communication device comprising:
 a memory, and   a processor operably coupled to the memory, wherein the processor, when executing program instructions stored in the memory, is configured to:
 cause the terminal to receive, from a base station, a random access preamble index corresponding to a random access preamble belonging to a non-contention based random access preamble group; 
 cause the terminal to generate, in response to receiving from the base station the random access preamble index, the corresponding random access preamble using the random access preamble index; 
 cause the terminal to transmit the random access preamble to a base station, wherein the random access preamble is associated with an identifier, and the identifier is determined based on a frequency and a time through which the random access preamble is transmitted; 
 cause the terminal to receive scheduling information from the base station through a control channel based on the identifier; and 
 cause the terminal to receive a random access response from the base station through a shared channel for data transmission, wherein the scheduling information indicates at least a frequency and a time of the random access response at the shared channel for data transmission. 
   
     
     
       30. The communication device of claim 29, wherein the random access response includes radio resource allocation information. 
     
     
       31. The communication device of claim 30, wherein the random access response further includes information on the random access preamble transmitted by the terminal. 
     
     
       32. The communication device of claim 25, wherein the random access response further includes information on the random access preamble transmitted by the mobile station.