Use Cases of using Extended Cyclic Prefix

You can refer to the following information:

5.2.1 Benefits

The CP technique mitigates ISI and ICI caused by multipath delay, ensuring network coverage in E-UTRAN cells.

The deployment suggestions of extended CP are as follows:

• It is recommended that extended CP be activated to improve uplink and downlink signal to interference plus noise ratios (SINRs) if the multipath delay spread exceeds the normal CP length of 4.7 μs in the area (the time difference is greater than the length of a normal CP, 4.7 μs), for example, where there are high buildings or mountains in the distance that will reflect signals. This condition can be interpreted as follows: There is at least 1.5 km difference between the line of sight (LOS) path of a signal arriving at a UE and the reflected path of the same signal last arriving at the UE.

• It is difficult to obtain the actual multipath delay spread. To evaluate whether to use extended CP, operators can estimate whether the multipath delay spread is longer than the normal CP length based on the building distribution and landform.

• UEs may not support extended CP. Enabling this function may cause exceptions of such UEs. It is not recommended that this function be enabled if there are such UEs on the live network. The extended CP capability of UEs depends on UEs themselves. NOTE:

  This capability cannot be identified through UE capability information. If a UE can access a cell with extended CP enabled and the UE data rate can reach its peak value, this indicates that the UE supports extended CP.

5.2.2 Impacts

Network Impacts

The use of extended CP causes more system overhead than the use of normal CP and therefore system capacity decreases.

Function Impacts

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