A communication system comprising: a user terminal; and a base station adapted to allocate frequency bands to the user terminal by using a continuous allocation scheme of continuously allocating resource blocks (10-1 to 10-24), wherein a single set of resource blocks (10-1 to 10-24), which are contiguous on the frequency axis, is allocated to the user terminal, and a discrete allocation scheme of discretely allocating resource blocks (10-1 to 10-24) for data transmission, wherein a plurality of sub-blocks are allocated to the user terminal, wherein each sub-block is composed of a number of resource blocks (10-1 to 10-24), and the discrete allocation is such that each sub-block consists of resource blocks (10-1 to 10-24) which are contiguous on the frequency axis, and the interval between sub-blocks is at least one resource block, wherein the base station transmits a control signal for indicating one allocation scheme selected from the continuous allocation scheme and the discrete allocation scheme, and indicating locations of two sub-blocks on a frequency axis when the discrete allocation scheme is indicated, wherein each sub-block comprises two or more resource blocks (10-1 to 10-24) and the sub-blocks are separated by an interval of at least one resource block, and the user terminal performs data transmission based on the control signal received from the base station, characterized in that the resource blocks (10-1 to 10-24) allocated to the user terminal are indicated with a first number of bits of the control signal, and a switching between the continuous allocation scheme and the discrete allocation scheme is indicated with another bit of the control signal and wherein the discrete allocation scheme is only allowed if the number of allocated resource blocks is greater than a first threshold and smaller than a second threshold. a user terminal; and a base station adapted to allocate frequency bands to the user terminal by using a continuous allocation scheme of continuously allocating resource blocks (10-1 to 10-24), wherein a single set of resource blocks (10-1 to 10-24), which are contiguous on the frequency axis, is allocated to the user terminal, and a discrete allocation scheme of discretely allocating resource blocks (10-1 to 10-24) for data transmission, wherein a plurality of sub-blocks are allocated to the user terminal, wherein each sub-block is composed of a number of resource blocks (10-1 to 10-24), and the discrete allocation is such that each sub-block consists of resource blocks (10-1 to 10-24) which are contiguous on the frequency axis, and the interval between sub-blocks is at least one resource block, wherein the base station transmits a control signal for indicating one allocation scheme selected from the continuous allocation scheme and the discrete allocation scheme, and indicating locations of two sub-blocks on a frequency axis when the discrete allocation scheme is indicated, wherein each sub-block comprises two or more resource blocks (10-1 to 10-24) and the sub-blocks are separated by an interval of at least one resource block, and the user terminal performs data transmission based on the control signal received from the base station, characterized in that the resource blocks (10-1 to 10-24) allocated to the user terminal are indicated with a first number of bits of the control signal, and a switching between the continuous allocation scheme and the discrete allocation scheme is indicated with another bit of the control signal and wherein the discrete allocation scheme is only allowed if the number of allocated resource blocks is greater than a first threshold and smaller than a second threshold.