Uplink control signaling in cellular telecommunication system
View Patent ↗A method, apparatus, and computer program for controlling allocation of control message fields in uplink transmission in a cellular telecommunication system are presented. Uplink control message fields are allocated to the resources of a physical uplink shared traffic channel according to an uplink transmission scheme selected for a user terminal. The control message fields are allocated so that transmission performance of the control messages is optimized for the selected uplink transmission scheme.
1. A method comprising:
selecting an uplink transmission scheme for a user terminal of a cellular telecommunication system;
determining physical uplink shared traffic channel resources of the user terminal;
allocating control message fields to resources of the physical uplink shared traffic channel according to the selected uplink transmission scheme so as to optimize transmission performance of control messages in the selected uplink transmission scheme; and
determining a number of control symbols to be allocated to a given control message field in the resources of the physical uplink shared traffic channel on the basis of the number of bits to be transmitted in the control message field, the total number of bits to be transmitted in the resources of the physical uplink shared traffic channel, the number of subcarriers in a symbol block, the number of symbol blocks per sub-frame, and a quality offset defining an offset between desired reception qualities of traffic data and control data transferred in the control message field;
coding the control symbols with a channel code selected on the basis of the determined number of control symbols; and
mapping the coded control symbols of the control message fields to the frequency resource elements of the symbol blocks according to the selected uplink transmission scheme.
2. The method of claim 1 , further comprising: determining the number of control symbols to be allocated to a given control message field in the resources of the physical uplink shared traffic channel on the basis of a difference between multipath channel ranks selected for the control message field and the traffic data when the selected uplink transmission scheme utilizes spatial multiplexing transmission in the uplink, in order to compensate for reduction in the size of the control message field when the rank of the control message field is lower than the rank of the traffic data.
3. An apparatus comprising:
a processor configured to select an uplink transmission scheme for a user terminal of a cellular telecommunication system,
to determine physical uplink shared traffic channel resources of the user terminal,
to allocate control message fields to the resources of the physical uplink shared traffic channel according to the selected uplink transmission scheme so as to optimize transmission performance of the control messages in the selected uplink transmission scheme;
wherein the processor is further configured to determine a number of control symbols to be allocated to a given control message field in the resources of the physical uplink shared traffic channel on the basis of the number of bits to be transmitted in the control message field, the total number of bits to be transmitted in the resources of the physical uplink shared traffic channel, the number of subcarriers in a symbol block, the number of symbol blocks per sub-frame, and a quality offset defining an offset between desired reception qualities of traffic data and control data transferred in the control message field;
to code the control symbols with a channel code selected on the basis of the determined number of control symbols; and to map the control symbols of the control message fields to the frequency resource elements of the symbol blocks according to the selected uplink transmission scheme.
4. The apparatus of claim 3 , wherein the processor is further configured to determine the number of control symbols to be allocated to a given control message field in the resources of the physical uplink shared traffic channel on the basis of a difference between multipath channel ranks selected for the control message field and the traffic data when the selected uplink transmission scheme utilizes spatial multiplexing transmission in the uplink, in order to compensate for reduction in the size of the control message field when the rank of the control message field is lower than the rank of the traffic data.
5. A computer program product comprising a non-transitory program memory readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a method that comprises:
selecting an uplink transmission scheme for a user terminal of a cellular telecommunication system;
determining physical uplink shared traffic channel resources of the user terminal;
allocating control message fields to resources of the physical uplink shared traffic channel according to the selected uplink transmission scheme so as to optimize transmission performance of control messages in the selected uplink transmission scheme; and
determining a number of control symbols to be allocated to a given control message field in the resources of the physical uplink shared traffic channel on the basis of the number of bits to be transmitted in the control message field, the total number of bits to be transmitted in the resources of the physical uplink shared traffic channel, the number of subcarriers in a symbol block, the number of symbol blocks per sub-frame, and a quality offset defining an offset between desired reception qualities of traffic data and control data transferred in the control message field;
coding the control symbols with a channel code selected on the basis of the determined number of control symbols; and
mapping the coded control symbols of the control message fields to the frequency resource elements of the symbol blocks according to the selected uplink transmission scheme.