JPL's Wireless Communication Reference Website

Chapter: Wireless Propagation Channels
Section: Multipath Fading, Fade Durations, Effective Throughput

 

Selecting the Packet Length

 

BER SPEC

This Special Purpose Embedded Calculator calculates the effective throughput over a radio link with Rayleigh fading. A block of data is assumed to be lost if the SNR drop below a threshold value during any portion of the packet transmission time. See: model and math.

Effective Throughput
Fade margin
Local-mean signal power relative to
minimum required signal power 		dB
Number of header bits
Includes all overhead, such as CRC 		bits
Number of user bits bits
Carrier frequency MHz
Speed of mobile km/h
Channel bit rate bit/s
 
 

Result:
Outage Prob  
Doppler Hz
Average nonfade duartion: second
Throughput: percent
  bit/s

Note 1.: In a TDMA or burst transmission system, only a fraction of the channel bit rate is available for a single user. It is essential that you use the channel bit rate in the above spreadsheet, as this determines the ratio between the packet duration and the non-fade durations of the channel.

Note 2.: Some systems, such as GSM, employ interleaving among blocks of data. This makes the model used here less realistic.


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