What does FDD mean in UNCLASSIFIED

Frequency Division Duplexing (FDD) is a networking technique used to enable simultaneous transmission of data in two different directions over the same frequency channel. In FDD, two separate and distinct frequencies are assigned for the uplink and downlink channels respectively so that both can be used simultaneously in full-duplex mode.

FDD works by dividing the available spectrum into two separate frequency bands, one for transmitting data from the source to the destination and one for transmitting data back from the destination to the source. This means that both devices can send and receive data simultaneously over the same spectrum using their respective frequencies.

Using FDD has several advantages including improved spectral efficiency, high spectral flexibility, better power control capabilities, easy amplification of signals and low interference levels between channels. Additionally, it provides good immunity from multipath fading due to the use of separate transmit and receive frequencies.

Applications such as digital cellular networks, wireless LANs, satellite communication systems and mobile radio systems are all suitable for deploying FDD because they require simultaneous bidirectional communication between stations.

In order to achieve channel division with FDD, two or more fixed frequency pairs called duplex channels are created in which each pair contains a dedicated uplink frequency band for transmissions from station A to station B and another dedicated downlink frequency band for transmissions from station B to station A. The number of these fixed frequency pairs created determines how many channels can be used concurrently.

Yes - one limitation is that due to its limited bandwidth, FDD cannot provide large amount of data throughput compared to other techniques like Time Division Multiple Access (TDMA). Additionally, since it requires two separate transceivers - one each for uplink and downlink - this increases overall cost associated with implementing an FDD system.

Yes - synchronization is necessary in order for successful communications between parties when using an FDD network. This involves both receivers synchronizing their local clocks with those of their respective remote counterparts so that transmitted frames are received in their entirety without any time alignment issues causing delays or errors during transmission.

Yes - by increasing transmit power coupled with careful power control optimization techniques such as link adaptation algorithms, it is possible to increase capacity within an existing infrastructure simply by allowing higher number of users access while still maintaining reliability in performance standards across all members of the network.