n Hardware cost Lower cost as no diplexer is needed to Diplexer is needed and the implementation isolate the transmitter and receiver cost is higher Channel Channel propagation is the same in both Channel characteristics are different in both reciprocity directions which enables estimation of the directions as a result of the use of different downlink channel from the uplink channel frequencies UL/DL It is possible to dynamically change the UL UL/DL bandwidths are determined by asymmetry and DL ratio based on the traffic volume in frequency allocation designated by the each direction regulatory authorities. It is therefore not possible to dynamically adapt to the traffic volume Guard period/ Guard period required to ensure uplink and Frequency separation is required to provide frequency downlink transmissions do not interfere. sufficient isolation between uplink and separation Large guard period will limit the capacity. downlink. However, large frequency Larger guard period normally required if separation does not impact the capacity. distances are increased to accommodate Note that a guard band in frequency larger propagation delays. Note that a domain is required to suppress interference guard band in frequency domain is required to adjacent bands. to suppress interference to adjacent bands. Discontinuous Discontinuous transmission is required to Continuous transmission is possible transmission allow both uplink and downlink transmissions. This can degrade the performance of the RF power amplifier in the transmitter Switching point Base stations are required to be Not applicable synchronization synchronized with respect to the uplink and downlink transmission times. If neighboring base stations use different uplink and downlink assignments and share the same channel, then interference may occur between cells. aA diplexer is a passive device that implements frequency domain multiplexing. Two ports are multiplexed onto a third port. The signals on each input ports occupy nonoverlapping frequency bands. Consequent