Authors propose a method for improving channel reservations in multi-subcarrier multiple-access wireless communications schemes. This scheme is designed for use with wide-area synchronous sensing zones that use functionally extended multi-subcarrier multiple-access subcarrier communication schemes for passive radio-frequency identification (RFID). When the sensing target is larger than the communication distance of the sensor, the sensing zone must be divided. Overlapping zones invariably occur in this case. Sensors in overlapping zones transmit signals to their respective receivers over the same channels and interference follows. If three or more zones are placed side by side, middle zone's communication capacity is lower than else zones. Because, middle zone can not use nearly center frequency. However, the communication capacity and its variations have not been examined for how they are affected by the zones in which overlapping sensors are used. This study investigated communications between sensors in overlapping zones by assigning channels to receivers in odd zones. The channel reservation method and the conventional method were simulated in MATLAB an compared. By allocating channels to sensors in odd zones, communication capacity can be improved and variations suppressed.