October 01, 2017

Practical LTE and WiFi Coexistence Techniques Beyond LBT

  • Khawer M.
  • Ling J.
  • Lopez-Perez D.

Coexistence with WiFi is the key issue for unlicensed band LTE. The main coexistence mechanism is listen-before-talk, whereby radio frequency energy is sensed over a short period and compared to a threshold. Given the default energy thresholds, the energy sensing range is much less than the cell range. Either technology can experience a collision due to transmissions being below energy detection threshold. Currently, WiFi is agnostic to unlicensed band LTE. To improve coexistence, a relay-based communications channel is proposed whereby LTE announces its presence. Legacy WiFi APs may be programmed to interpret and respond by firmware upgrade. Higher performance for both networks is demonstrated via more effective radio frequency channel selection and adaptive energy detection thresholding.

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