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LAUNCHXL-CC1350: High speed mode

sudhir mishra
Expert 1100 points
Part Number: LAUNCHXL-CC1350

Hi,

Please tell what exactly in HSM?

1. Which modulation used in this mode?

2. What is the Physical data rate in this mode?

I get 109 Kbps(Kilo Bit/Sec) rate if using this configuration -

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Node Freq Pkts Interval(ms) Mode Bytes Sent Time Sec Rate(Kbps)
1 TX node 868 TRIG NOW HSM 20000 1.475726 109
RX node 868 20000 1.515598 106
  • 0
    TI__Guru**** 317180 points
    See e2e.ti.com/.../548001

    Have you actually looked at the actual time between packets? Is this for 256 bytes packets?
  • 0 in reply to TER
    Expert 1100 points

    Payload length is :200 byte and sending 100 packets.
    I want to know the actual time between packets how to calculate it.

  • 0 in reply to sudhir mishra
    TI__Guru**** 317180 points
    The effective data rate throughput through the system will be lower than the on the air data rate. The effective data rate throughput is dependent on the packet loss ratio as well as the total time or overhead for sending a packet. The total time for sending a packet is as follows,

    ~50 us CMD_TX_HS command parsing (with startToTxRatOffset = 0xA0).

    ~50 us PA Ramp Up.

    104/130 us Total Preamble (5 Mbps / 4 Mbps)

    1.6/2.0 us/Byte Data Payload (5 Mbps / 4 Mbps)

    ~30 us PA ramp down, final command housekeeping

    So the total time for sending a packet adds up to ~234 us command overhead for the 5 Mbps mode and ~260 us command overhead for the 4 Mbps mode. Then using the total time for sending the packet can be used together with the packet loss ratio and the system data rate throughput can be calculated as follows,

    Throughput (P) = PSR * Data / Time = 8*N / (234 + 1.6*N) where N is in Bytes and P in Mbps and PSR is “Packet Success Rate” (1-PER) in the [0,1] range

    For a given P [Mbps], then N = 234*(P/PSR) / (8-1.6*(P/PSR))

    If P = 3 [Mbps], PSR=0.95, then N = 251 bytes per packet.