It is very common for telecom Operators within the TDD band of LTE have a wider unpaired spectrum than the bandwidth defined maximum carrier bandwidth of 20MHz. As a result, the selection of carrier bandwidth for multiple carrier condition is also more complex in TDD than FDD.
Moreover, the coexistence of WiMAX within the same TDD spectrum is also very common and this has further complicated the carrier and bandwidth planning for LTE TDD network from a carrier planning perspective.
Planning engineers need to take all these variations along with customer throughput and coverage requirement into account when it comes to TDD frequency planning.
Besides, carrier bandwidth, co-frequency and time sharing nature between uplink and downlink in TDD also require careful selection of guard band and pilot time slot (DwPTS, GP and UpPTS).
Failure to include enough separation will create a lot of co-channel interference which will degrade the throughput performance significantly.
Lastly, for TDD to work properly, all cells must be operating in time synchronous mode to avoid any extra interference being introduced to the network. IEEE 1588v2 implementation is recommended and will help to ensure the integrity of time synchronization within the LTE TDD network.