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All, We’ve had an assumption in 1904.3 that the endpoints in a link will be synchronized by some method; there are multiple methods to get this synchronization (GNSS/GPS, 1588, SyncE, CSAC, BITS, etc.), so we did not want to prescribe the method
of synchronization in 1904.3. Can we bound what the expectations are for this synchronization, at least up through LTE? (5G is still in definition.) ·
For example, proper handoff between cells requires that the cells be synchronized to within 3 µs. This means that if all cells are within ±1.5 µs of “true time” like TAI, then the cells can do proper handover. ·
Under LTE Advanced, this is reduced to ± 1 µs. ·
The tightest synchronization requirement I see in the current 3GPP requirements is in 3GPP TS 36.104 (there are similar requirements in 3GPP TS 25.104 and 3GPP TS 36.133 as well): 6.5.3.1 Minimum Requirement
For MIMO or TX diversity transmissions, at each carrier frequency, TAE shall not exceed 65 ns. For intra-band contiguous carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 130 ns. For intra-band non-contiguous carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 260 ns. For inter-band carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 1.3 μs. For discussion purposes, can we agree that synchronization requirements for RoE nodes is somewhere in the range of ±65 ns to ±1.5 µs? --kb ------------------------------------------------------------------ |