Communication system

Abstract

A communication method which uses a plurality of sub-carriers grouped in a sequence of chunks, the method includes receiving uplink data from one or more user devices and generating corresponding ACK/NACK messages for the received data, forming control data defining an allocation of one or more chunks of the sub-carriers for each of a plurality of user devices, transmitting the control data to the user devices, and transmitting the ACK/NACK messages to the corresponding user devices, wherein the control data for each user device is transmitted over a control channel using a first subset of the plurality of sub-carriers and the ACK/NACK messages for each user device are transmitted over an ACK/NACK channel that is separate from the control channel using a second different subset of the plurality of sub-carriers.

1 . A communication method which uses a plurality of sub-carriers grouped in a sequence of chunks, the method comprising:
 receiving uplink data from one or more user devices and generating corresponding ACK/NACK messages for the received data;   forming control data defining an allocation of one or more chunks of said sub-carriers for each of a plurality of user devices;   transmitting said control data to said user devices; and   transmitting said ACK/NACK messages to the corresponding user devices;   wherein the control data for each user device is transmitted over a control channel using a first subset of said plurality of sub-carriers and the ACK/NACK messages for each user device are transmitted over an ACK/NACK channel that is separate from said control channel using a second different subset of said plurality of sub-carriers.   
     
     
         2 . A method according to  claim 1 , wherein said forming forms control data that allocates said one or more chunks of sub-carriers to each of said user devices for use in transmitting uplink data, optionally wherein said generating generates an ACK/NACK message for the data received on each chunk of sub-carriers, and/or optionally wherein said transmitting transmits each ACK/NACK message in a respective ACK/NACK channel, each formed using a respective one or more sub-carriers from said second subset. 
     
     
         3 . A method according to  claim 1 , wherein said forming forms two types of control data, one for user devices that are scheduled to receive downlink data and one for user devices that are scheduled to transmit uplink data, optionally wherein at least one of said first and second types of control data includes padding data so that each type of control channel is of the same size, and/or optionally wherein each type of control data corresponds in size to two chunks of sub-carriers. 
     
     
         4 . A method according to  claim 1 , further comprising forming respective control data for each user device scheduled to transmit and/or receive data in a current sub-frame and transmitting the respective control data to the corresponding user device over a channel that is dedicated to the user device. 
     
     
         5 . A method according to  claim 1  which uses a plurality of sub-hands, each of which comprises sub-carriers arranged in a sequence of chunks, and further comprising generating respective control data for sub-carrier allocation in each sub-band, optionally wherein the control data for a sub-band is signalled within that sub-band. 
     
     
         6 . A method according to  claim 1 , wherein a separate control channel is provided for each user device scheduled in a current sub-frame and wherein a maximum number of user devices can be scheduled within the current sub-frame, optionally wherein when the number of user devices to be scheduled in a current sub-frame is less than said maximum, some of the control channel resources are freed and occupied by user data, and/or optionally wherein the absence of a control channel is indicated using a single bit field in a preceding control channel. 
     
     
         7 . A method according to  claim 1 , further comprising allocating a resource to be used for an ACK/NACK message for a user device and transmitting data identifying said allocated ACK/NACK resource to the user device, optionally comprising transmitting said data identifying said allocated ACK/NACK resource within said control channel, and/or optionally wherein said data identifying said ACK/NACK resource comprises an index identifying each resource. 
     
     
         8 . A method according to  claim 1 , further comprising determining the sub-carriers used to acknowledge received data in dependence upon an chunk number allocated to the user device that transmitted the data to be acknowledged. 
     
     
         9 . A communication method which uses a plurality of sub-carriers grouped in a sequence of chunks, the method comprising:
 receiving control data defining an allocation of one or more chunks of said sub-carriers;   transmitting uplink data using the allocated sub-carriers; and   receiving ACK/NACK messages for the transmitted uplink data;   wherein said control data is received over a control channel using a first subset of said plurality of sub-carriers and said ACK/NACK messages are received on an ACK/NACK channel that is separate from said control channel using a second different subset of said plurality of sub-carriers.   
     
     
         10 . A method according to  claim 9 , wherein said received control data identifies one or more chunks of sub-carriers to be used for transmitting said uplink data, optionally wherein said receiving receives an ACK/NACK message for the uplink data transmitted on each chunk of sub-carriers, and/or optionally wherein said receiving receives each ACK/NACK message in a respective ACK/NACK channel, each formed using a respective one or more sub-carriers from said second subset. 
     
     
         11 . A method according to  claim 9 , further comprising determining the sub-carriers that will be used to acknowledge transmitted uplink data in dependence upon a chunk number allocated to the user device that transmitted the data to be acknowledged. 
     
     
         12 . A method according to  claim 9 , which uses a plurality of sub-bands, each of which comprises sub-carriers arranged in a sequence of chunks, and further comprising receiving respective control data for sub-carrier allocation in each sub-band, optionally wherein the control data for a sub-band is signalled within that sub-band, optionally further comprising receiving data identifying an allocated ACK/NACK resource on which to receive ACK/NACK messages, optionally wherein said receiving receives said data identifying said allocated ACK/NACK resource within said control channel, and/or optionally wherein said data identifying said ACK/NACK resource comprises an index identifying each resource and determining the allocated resource from said index. 
     
     
         13 . A computer program product comprising computer implementable instructions for causing a programmable computer device to perform the method of  claim 1 . 
     
     
         14 . A communications node which is operable to communicate with a plurality of user devices using a plurality of sub-carriers grouped in a sequence of chunks, the communications node comprising:
 a receiver operable to receive uplink data from one or more user devices and operable to generate corresponding ACK/NACK messages for the received data;   a controller operable to form control data defining an allocation of one or more chunks of said sub-carriers for each of a plurality of user devices;   a transmitter operable to transmit said control data to said user devices and to transmit said ACK/NACK messages to the corresponding user devices;   wherein said transmitter is operable to transmit said control data to each user device over a control channel using a first subset of said plurality of sub-carriers and to transmit said ACK/NACK messages on an ACK/NACK channel that is separate from said control channel using a second different subset of said plurality of sub-carriers.   
     
     
         15 . A user device which is operable to communicate with a communication node which is operable to communicate with a plurality of user devices using a plurality of sub-carriers grouped in a sequence of chunks, the user device comprising:
 a receiver operable to receive control data defining an allocation of one or more chunks of said sub-carriers; and   a transmitter operable to transmit uplink data using the allocated sub-carriers;   wherein said receiver is also operable to receive ACK/NACK messages for the transmitted uplink data; wherein said receiver is operable to receive said control data over a control channel using a first subset of said plurality of sub-carriers and to receive said ACK/NACK messages on an ACK/NACK channel that is separate from said control channel using a second different subset of said plurality of sub-carriers.