Random access channel priorization scheme

Abstract

The present invention relates to a method and to devices for transmitting and receiving data in a code division multiple access telecommunication system. A random access time window (20) is provided, which comprises a plurality of random access slots for transmitting random access data, for example from a mobile station (24) to a base station (25). The plurality of random access slots in the random access time window (20) is divided into at least two groups, whereby the groups are allocated to respective priority classes, whereby the priority classes represent the transmission priorities of the random access data to be transmitted in the random access slots. The present invention allows a reduction in congestion on the random access slots for certain access types at the expense of other access types and a more efficient use of the random access time window.

What is claimed is: 
     
       1. Method for transmitting and receiving data in a code division multiple access telecommunication system, comprising the steps of:
 providing a random access time window comprising a plurality of random access slots for transmitting random access data from at least one first communication device to a second communication device, and 
 dividing the plurality of random access slots of the random access time window into at least two groups each having a respective initial size, and 
 allocating the groups to respective priority classes, 
 whereby the priority classes represent the transmission priorities of the random access data to be transmitted in the random access slots, 
 whereby the size of at least one of said groups is changed in accordance with changing needs such that a probability of access for the at least one group is dynamically changed, and 
 whereby contents of one of said groups are permitted to overlap with another of said groups. 
 
     
     
       2. Method for transmitting and receiving data according to  claim 1 , characterized in,
 that the transmission priorities of the random access data to be transmitted are determined on the basis of the content and the type of the random access data. 
 
     
     
       3. Method for transmitting and receiving data according to  claim 1  characterized in,
 that the number of random access slots in each group is variably set depending on system requirements. 
 
     
     
       4. Method for transmitting and receiving data according to  claim 1 , characterized in,
 that a first communication device, for transmitting random access data of a certain transmission priority, randomly chooses one or more random access slots from the group having the corresponding priority class. 
 
     
     
       5. Method for transmitting and receiving data according to  claim 4 , characterized in,
 that the access probability depends on the number of random access slots in the group. 
 
     
     
       6. Method for transmitting and receiving data according to  claim 1 , characterized in,
 that said second communication device periodically broadcasts information defining the groups of the random access time window to the at least one first communication device. 
 
     
     
       7. Method for transmitting and receiving data according to  claim 1 , characterized in,
 that each random access slot in said random access time window is defined by a time offset value and a preamble code. 
 
     
     
       8. Device for transmitting and receiving data in a code division multiple access telecommunication system,
 in which a random access time window comprising a plurality of random access slots for transmitting random access data is provided, 
 the plurality of random access slots of the random access time window being divided into at least two groups each having a respective initial size, and 
 the groups being allocated to respective priority classes, 
 whereby the priority classes represent the transmission priorities of the random access data to be transmitted in the random access slots, 
 with means for randomly choosing one or more random access slots from a group having a certain priority class corresponding to the transmission priority of the random access data to be transmitted, 
 means for transmitting the random access data in said chosen random access slot(s), 
 whereby the size of at least one of said groups is changed in accordance with changing needs such that a probability of access for the at least one group is dynamically changed, and 
 whereby contents of one of said groups are permitted to overlap with another of said groups. 
 
     
     
       9. Device for transmitting and receiving data according to  claim 8 , characterized in,
 that the access probability depends on the number of random access slots in the group. 
 
     
     
       10. Device for transmitting and receiving data according to  claim 8 , characterized by,
 means for extracting information defining the groups of the random access time window from a received broadcast signal. 
 
     
     
       11. Device for transmitting and receiving data according to  claim 8 , characterized in,
 that each random access slot in said random access time window is defined by a time offset value and a preamble code. 
 
     
     
       12. Device for transmitting and receiving data in a code division multiple access telecommunication system,
 in which a random access time window comprising a plurality of random access slots for transmitting random access data is provided, 
 with means for dividing the plurality of random access slots of the random access time window into at least two groups each having a respective initial size, 
 whereby the groups are allocated to respective priority classes, the priority classes representing the transmission priorities of the random access data to be transmitted in the random access slots, 
 means for transmitting information defining the groups of the random access time window, 
 whereby the size of at least one of said groups is changed in accordance with changing needs such that a probability of access for the at least one group is dynamically changed, and 
 whereby contents of one of said groups are permitted to overlap with another of said groups. 
 
     
     
       13. Device for transmitting and receiving data according to  claim 12 , characterized in,
 that the transmission priorities of the random access data to be transmitted are determined on the basis of the content and the type of the random access data. 
 
     
     
       14. Device for transmitting and receiving data according to  claim 12 , characterized in,
 that said means for dividing the random access slots into groups sets the number of random access slots in each group variably depending on system requirements. 
 
     
     
       15. Device for transmitting and receiving data according to  claim 12 , characterized in,
 that each random access slot in said random access time window is defined by a time offset value and a preamble code. 
 
     
     
       16. Method for transmitting and receiving data in a code division multiple access telecommunication system, comprising the steps of:
 providing random access resources containing a plurality of random access slots for transmitting random access data;   dividing the random access resources by assigning a signature which is available as one of 16 separate codes in accordance with priority classes which represent transmission priorities of the random access data to be transmitted; and   randomly choosing one or more random access slots from the divided random access resource having the priority class corresponding to the transmission priority of the random access data to be transmitted in order to allocate the random access data into the one or more random access slots within the divided random access resource.   
     
     
       17. A device for transmitting and receiving data in a code division multiple access telecommunication system having random access resources containing a plurality of random access slots for transmitting random access data, said device comprising;
 means for dividing the random access resources by assigning a signature which is available as one of 16 separate codes in accordance with priority classes which represent transmission priorities of the random access data to be transmitted; and   means for randomly choosing one or more random access slots from the divided random access resource having the priority class corresponding to the transmission priority of the random access data to be transmitted in order to allocate the random access data into the one or more random access slots within the divided random access resource.   
     
     
       18. Method for transmitting and receiving data in a code division multiple access (CDMA) telecommunication system having a base station and plural mobile stations, comprising the steps of;
 providing random access resources containing a plurality of random access slots for transmitting random access data;   selecting an available signature from 16 separate codes for differentiating one cell of the CDMA telecommunication system from another cell in accordance with priority classes which represent the transmission priorities of the random access data to be transmitted; and   broadcasting the selected signature to a mobile station to enable the mobile station to randomly choose one or more random access slots corresponding to the selected signature.   
     
     
       19. Apparatus for transmitting and receiving data in a code division multiple access (CDMA) telecommunication system having random access resources containing a plurality of random access slots for transmitting random access data, said CDMA telecommunication system having a base station and plural mobile stations, said apparatus comprising:
 means for selecting an available signature from 16 separate codes for differentiating one cell of the CDMA telecommunication system from another cell in accordance with priority classes which represent the transmission priorities of the random access data to be transmitted; and   a transmitter for broadcasting the selected signature to a mobile station to enable the mobile station to randomly choose one or more random access slots corresponding to the selected signature.   
     
     
       20. Method for transmitting and receiving data in a code division multiple access telecommunication system, comprising the steps of;
 providing random access resources containing a plurality of random access slots for transmitting random access data;   dividing the random access resources by assigning a signature which is available as one of 16 separate codes on the basis of content and type of the random access data; and   randomly choosing one or more random access slots from the divided random access resource corresponding to the content and type of the random access to be transmitted in order to allocate the random access data into the one or more random access slots within the divided random access resource.   
     
     
       21. A device for transmitting and receiving data in a code division multiple access telecommunication system having random access resources containing a plurality of random access slots for transmitting random access data, said device comprising:
 means for dividing the random access resources by assigning a signature which is available as one of 16 separate codes on the basis of content and type of the random access data; and   means for randomly choosing one or more random access slots from the divided random access resource corresponding to the content and type of the random access to be transmitted in order to allocate the random access data into the one or more random access slots within the divided random access resource.   
     
     
       22. Method for transmitting and receiving data in a code division multiple access telecommunication system, comprising the steps of
 providing a random access channel containing a plurality of random access slots for transmitting random access data, whereby each random access slot is defined by a time offset value and a preamble signature, and   allocating the plurality of random access slots to different priority classes on the basis of the time offset values and preamble signatures, the priority classes representing transmission priorities of the random access data to be transmitted in the random access slots.   
     
     
       23. A device for transmitting and receiving data in a code division multiple access telecommunication system, comprising;
 means for providing a random access channel containing a plurality of random access slots for transmitting random access data, wherein each random access slot is defined by a time offset value and a preamble signature, and   means for allocating the plurality of random access slots to different priority classes on the basis of the time offset values and preamble signatures, the priority classes representing transmission priorities of the random access data to be transmitted in the random access slots.   
     
     
       24. Method for transmitting and receiving data in a code division multiple access telecommunication system in which a communication area is divided into cells, comprising the steps of
 providing a random access channel containing a plurality of random access slots for transmitting random access data, whereby each random access slot is defined by a preamble signature which is one of a plurality of signature codes differentiating the cells from each other, and   allocating the plurality of random access slots to different priority classes on the basis of the preamble signatures, the priority classes representing transmission priorities of the random access data to be transmitted in the random access slots.   
     
     
       25. A device for transmitting and receiving data in a code division multiple access telecommunication system in which a communication area is divided into cells, comprising:
 means for providing a random access channel containing a plurality of random access slots for transmitting random access data, whereby each random access slot is defined by a preamble signature which is one of a plurality of signature codes differentiating the cells from each other, and   means for allocating the plurality of random access slots to different priority classes on the basis of the preamble signatures, the priority classes representing transmission priorities of the random access data to be transmitted in the random access slots.   
     
     
       26. Method for transmitting and receiving data in a code division multiple access telecommunication system, comprising the steps of
 providing a random access channel containing a plurality of random access slots for transmitting random access data, whereby each random access slot is defined by a preamble signature,   broadcasting preamble signature information to a communication device of the telecommunication system, and   randomly choosing at said communication device a random access slot on the basis of the received preamble signature information and transmitting random access data in the chosen random access slot.   
     
     
       27. Apparatus for transmitting and receiving data in a code division multiple access telecommunication system having a random access channel containing a plurality of random access slots for transmitting random access data, whereby each random access slot is defined by a preamble signature, said apparatus comprising:
 means for broadcasting preamble signature information to a communication device of the telecommunication system, and   said communication device including means for randomly choosing a random access slot on the basis of the received preamble signature information and means for transmitting random access data in the chosen random access slot.   
     
     
       28. Method for transmitting and receiving data in a code division multiple access telecommunication system, comprising the steps of:
 providing a random access time window comprising a plurality of random access slots for transmitting random access data from at least one first communication device to a second communication device,   dividing the plurality of random access slots of the random access time window into at least two groups each having a respective initial size, and   allocating the groups to respective priority classes,   whereby the priority classes represent the transmission priorities of the random access data to be transmitted in the random access slots,   whereby the size of at least one of said groups can be changed in accordance with changing needs such that a probability of access for the at least one group can be changed dynamically; and   whereby contents of one of said groups are permitted to overlap with another of said groups.   
     
     
       29. Device for transmitting and receiving data in a code division multiple access telecommunication system,
 in which a random access time window comprising a plurality of random access slots for transmitting random access data is provided,   the plurality of random access slots of the random access time window being divided into at least two groups each having a respective initial size, and   the groups being allocated to respective priority classes,   whereby the priority classes represent the transmission priorities of the random access data to be transmitted in the random access slots,   means for randomly choosing one or more random access slots from a group having a certain priority class corresponding to the transmission priority of the random access data to be transmitted,   means for transmitting the random access data in said chosen one or more random access slot,   whereby the size of at least one of said groups can be changed in accordance with changing needs such that a probability of access for the at least one group can be changed dynamically; and   whereby contents of one of said groups are permitted to overlap with another of said groups.