802.16d PHY – TDD
Fixed WiMAX (802.16d) PHY - TDD
- Uplink & Downlink transmission shares the same frequency.
- Uplink & Downlink transmission are separated in time.
- TDD Frame has a fixed duration.
- A TDD frame contains one uplink & one downlink subframe.
- TDD Framing is adaptive i.e capacity allocated to downlink versus uplink may vary.
- Tx/Rx Transition Gap (TTG) between downlink burst & subsequent uplink burst allows time for BS to switch from Tx mode to Rx mode and SS to Rx mode to Tx mode.
- BS looks for first symbols of uplink burst after TTG.
- Rx/Tx Transition Gap (RTG) between uplink burst & subsequent downlink burst allows time for BS to switch from Rx mode to Tx mode and SS to Tx mode to Rx mode.
- SS looks for first symbols of modulated data in downlink burst after RTG
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