A method in a base station for allocating blocks of radio resources (BR DL, BR UL) to mobile terminals in downlink frames (TR DL) transmitted by the base station and in uplink frames (TR UL) received from the mobile terminals, the blocks of resources being time and frequency divided in the frames, characterised in that it comprises: - configuring each downlink frame (TR DL) into first and second areas (ZP DL, ZMC DL) reserved for data to be transmitted respectively to first and second mobile terminals (MT P, MT G0) and each uplink frame (TR UL) into first and second areas (ZP UL, ZMC UL) reserved for data to be received respectively from the first and second terminals, - allocating blocks of resources in the first areas (ZP DL, ZP UL) of the downlink and uplink frames shared between data to be transmitted to and received from the first mobile terminals (MT P), the positions of a block of resources allocated to data to be transmitted to a first terminal and of a block of resources allocated to data to be received from the first terminal being variable in the first areas, said method being characterised in that it includes: - configuring the second area (ZMC DL) of each downlink frame (TR DL) into first sub-channels reserved for data to be transmitted respectively to groups (G0, G1, G2) of second mobile terminals (MT G0, MT G1, MT G2), the first sub-channels having predetermined rates and each consisting in at least one block of resources having a predetermined position in the second area of downlink frames, and configuring the second area (ZMC DL) of each uplink frame (TR UL) into second sub-channels reserved for data to be received respectively from the groups of second terminals, the second sub-channels having predetermined rates and each consisting in at least one block of resources having a predetermined position in the second area of the uplink frames, - allocating the first sub-channels as a priority to data to be transmitted respectively to the groups (G0, G1, G2) of second terminals, and - allocating a second sub-channel reserved for a group as a priority to data to be received from one of the second terminals (MT G0, MT G1, MT G2) of the group; signalling fields (SGMC DL, SGMC UL) at the beginning of the second areas (ZMC DL, ZMC DL) of the downlink and uplink frames (TR DL, TR UL) being allocated to signalling downlinks and uplinks associated with the groups (G0, G1, G2) and to scheduling the blocks of resources (BRG DL, BRG UL) of the downlink and uplink sub-channels respectively associated with the groups in the frames. - configuring each downlink frame (TR DL) into first and second areas (ZP DL, ZMC DL) reserved for data to be transmitted respectively to first and second mobile terminals (MT P, MT G0) and each uplink frame (TR UL) into first and second areas (ZP UL, ZMC UL) reserved for data to be received respectively from the first and second terminals, - allocating blocks of resources in the first areas (ZP DL, ZP UL) of the downlink and uplink frames shared between data to be transmitted to and received from the first mobile terminals (MT P), the positions of a block of resources allocated to data to be transmitted to a first terminal and of a block of resources allocated to data to be received from the first terminal being variable in the first areas, - configuring the second area (ZMC DL) of each downlink frame (TR DL) into first sub-channels reserved for data to be transmitted respectively to groups (G0, G1, G2) of second mobile terminals (MT G0, MT G1, MT G2), the first sub-channels having predetermined rates and each consisting in at least one block of resources having a predetermined position in the second area of downlink frames, and configuring the second area (ZMC DL) of each uplink frame (TR UL) into second sub-channels reserved for data to be received respectively from the groups of second terminals, the second sub-channels having predetermined rates and each consisting in at least one block of resources having a predetermined position in the second area of the uplink frames, - allocating the first sub-channels as a priority to data to be transmitted respectively to the groups (G0, G1, G2) of second terminals, and - allocating a second sub-channel reserved for a group as a priority to data to be received from one of the second terminals (MT G0, MT G1, MT G2) of the group;