Abstract: In a wireless communications system, a base station unit covers a plurality of communications station units and downlink and uplink communication between the base station unit and the communications station unit are wireless. Each of the communications station units covered by the base station unit is assigned to one of a plurality of groups that perform receiving or sending in the same time band. Each group's communication time band is made different for downlink and uplink communication. The downlink communication and uplink communication between the base station unit and plurality of communications station units is performed in time-division multiplexing regarding each of the plurality of groups to achieve a good assignment of groups. At the time of group assignment, the total amount of sending and receiving are adjusted for each group based on the traffic situation in order to reduce the empty time in downlink communication and uplink communication.

Abstract: In a wireless communications system, a base station unit covers a plurality of communications station units and downlink communication from the base station unit to the communications station unit and uplink communication from the communications station unit to the base station unit are performed wirelessly. In this system, each of the communications station units covered by the base station unit is assigned to one of a plurality of groups that perform receiving or sending in the same time band. Each group's communication time band is made different for downlink communication and for uplink communication. The downlink communication and uplink communication between the base station unit and plurality of communications station units is performed in time-division multiplexing regarding each of the plurality of groups to achieve a good assignment of groups.

Abstract: In an improved image data transmission system, an image data partitioning unit is provided at the transmitter section to partition an input image data into a predetermined number of picture elements (blocks) so that same picture elements of the image data can be subject to source image encoding and forward error correction encoding. At the receiver section, picture elements in each of the data blocks are subject to error correction decoding and source image decoding. The receiver section is provided with an image data interpolator which works, when an transmission error is detected, to interpolate with a substitution data the data in a block in which the error has been detected or data in other block to which the error has been propagated as it is. After the interpolation, a reconstructed image data is delivered.