Method and Devices for Communicating Over a Radio Channel

Abstract

The invention relates to methods and communication devices for transmitting data on a radio channel comprising the steps of determining a first preamble format to be used in a cell of the second communication device, determining a basic cyclic shift value from a set of basic cyclic shift values, the set is selected based on the preamble format, and transmitting data comprising indication of the determined first preamble format and a basic cyclic shift value pointer indicating the basic cyclic shift value in the set of basic cyclic shift values.

1 . A method in a base station for transmitting data on a radio channel comprising the steps of:
 determining a first preamble format to be used in a cell of the base station, the method is characterized in   determining a basic cyclic shift value from a set of basic cyclic shift values, the set to use is indicated by the preamble format, and   transmitting data comprising indication of the determined first preamble format and a basic cyclic shift value pointer indicating the basic cyclic shift value in the set of basic cyclic shift values.   
     
     
         2 . A method according to  claim 1 , wherein the step of determining the basic cyclic shift value comprises to select a basic cyclic shift value from the set of basic cyclic shift values, and wherein the set is one set of at least two sets of basic cyclic shift values, wherein each set is related to different preamble formats. 
     
     
         3 . A method according to  claim 1 , wherein the steps of determining the first preamble format and the basic cyclic shift value is based on the size of the cell. 
     
     
         4 . A method according to  claim 1 , wherein each preamble format corresponds to a set of basic cyclic shift values. 
     
     
         5 . A method according to  claim 1 , wherein the data is transmitted on a broadcast channel. 
     
     
         6 . A base station comprising a control unit arranged to determine a first preamble format to be used in a cell of the base station and to determine a basic cyclic shift value from a set of basic cyclic shift values, wherein the set to use is indicated by the first preamble format and the base station further comprises a transmitting arrangement adapted to transmit data comprising indication of the determined first preamble format and a basic cyclic shift value pointer indicating the basic cyclic shift value in the set of basic cyclic shift values. 
     
     
         7 . A base station according to  claim 6 , further comprising a receiving arrangement adapted to receive random access data from a user equipment, wherein the control unit is arranged to process the received data. 
     
     
         8 . A base station according to  claim 6 , further comprising a memory, wherein the control unit is arranged to select the basic cyclic shift value in the set of basic cyclic shift values, the set being one of at least two sets stored in the memory, wherein each set is related to different preamble formats. 
     
     
         9 . A base station according to  claim 6 , wherein the transmitting arrangement is adapted to transmit data on a broadcast channel. 
     
     
         10 . A method in a user equipment for processing a signal comprising the steps of:
 receiving data from a base station on a radio channel, the data comprises an indication of preamble format and a basic cyclic shift value pointer indicating the basic cyclic shift value to be used in a random access procedure,   determining the preamble format from the received data, and   selecting a basic cyclic shift value in a set of basic cyclic shift values, the set to use is indicated by the preamble format, based on the basic cyclic shift value pointer.   
     
     
         11 . A method according to  claim 10 , wherein the method further comprises a step of setting up the user equipment in an operational mode to perform a random access procedure using the determined preamble format and a preamble sequence that is cyclically shifted using a cyclic shift value that is based upon the determined basic cyclic shift value. 
     
     
         12 . A method according to  claim 10 , wherein the step of selecting the basic cyclic shift value comprises to select a basic cyclic shift value from a set of basic cyclic shift values of at least two sets of basic cyclic shift values, wherein the set to select from is based on the determined preamble format. 
     
     
         13 . A method according to  claim 10 , wherein each preamble format corresponds to a set of basic cyclic shift values. 
     
     
         14 . A method according to  claim 10 , wherein the set of basic cyclic shift values is a table of basic cyclic shift values and the received data comprises bits indicating the basic cyclic shift value, wherein the bits are the basic cyclic shift value pointer in the table and the preamble format indicates which table to use. 
     
     
         15 . A method according to  claim 10 , wherein the random access procedure comprises a preamble containing a guard time and/or a cyclic prefix, wherein the cyclic prefix and/or the guard time is determined as a function of the basic cyclic shift value. 
     
     
         16 . A method according to  claim 10 , wherein the data is received on a broadcast channel. 
     
     
         17 . A user equipment comprising a receiving arrangement adapted to receive data comprising a basic cyclic shift value pointer indicating a basic cyclic shift value and an indication of a first preamble format from base station on a radio channel, wherein a control unit is arranged to determine a preamble format to be used in a random access procedure from the indication in the received data and to select a basic cyclic shift value in a set of basic cyclic shift values based on the basic cyclic shift value pointer, wherein the set to use is indicated by the preamble format. 
     
     
         18 . A user equipment according to  claim 17 , wherein the control unit is further arranged to perform a random access procedure using the determined preamble format and a preamble sequence that is cyclically shifted in accordance with the selected basic cyclic shift value. 
     
     
         19 . A user equipment according to  claim 18 , further comprising a transmitting arrangement adapted to transmit the preamble sequence to the base station. 
     
     
         20 . A user equipment according to  claim 17 , further comprising a memory, wherein the control unit is arranged to select the basic cyclic shift value in the set of basic cyclic shift values, the set being one of at least two sets stored in the memory, wherein each set is related to different preamble formats. 
     
     
         21 . A user equipment according to  claim 17 , wherein the receiving arrangement is adapted to receive data on a broadcast channel.