Chapter 3: System planning
Link planning
Page 3-27
Calculation example for PTP topology
Suppose that the link characteristics are:
•
Link Symmetry = 1:1
•
Link Mode Optimization = TDM
•
Modulation Mode = 64QAM 0.92 Dual
•
Channel Bandwidth = 10 MHz
•
Link Range = 60 km
The calculation procedure for this example is as follows:
1
Use
to look up the data throughput capacity rates:
Tx = 41.30 Mbits/s
Rx = 41.30 Mbits/s
Aggregated = 82.61 Mbits/s
2
Use
to look up the Throughput Factor for 1:1, TDM, 10 MHz and Link Range 60 km.
The factor is 0.86.
3
Multiply the rates from Step 1 by the Throughput Factor from Step 2 to give the throughput
capacity of the link:
Tx = 35.52 Mbits/s
Rx = 35.52 Mbits/s
Aggregated = 71.04 Mbits/s
Calculation procedure for HCMP topology
To calculate the data rate capacity of a PTP 670 link, with or without TDD synchronization,
proceed as follows:
1 Use
to look up the TDD frame duration for the required
combination of:
•
Channel bandwidth
•
Maximum link range
•
Maximum number of Slaves
2 Use
to look up the one-way data capacity per time slot for the required
combination of:
•
Channel bandwidth
•
TDD frame duration
•
Modulation mode
3 The one-way capacity for a single Slave is the capacity per time slot multiplied by the number
of timeslots. The aggregate (two-way) capacity for one Slave is the sum of two one-way
capacities. The aggregate capacity for the Master is the capacity for one Slave multiplied by
the number of Slaves.
