Preliminary Coexistence Tests The same wireless signal was used as the victim: – Power Level = 0 dBm – BW = 20 MHz – Center Frequency = GHz – Orthogonal frequency-division multiplexing (OFDM) Data Rate = 6 Mbps – BPSK

OFDM concept Transmit data is spread over a number of orthogonal subcarriers in the frequency domain

Error vector magnitude (EVM) measurement of the receive signal constellation

Comparing Impacts of Different Interference Modulation/Technologies Setup – Currently conductive – Eventually move to radiated Target protocol – WLAN Interfering Modulation/Technologies – CW AM Signal – Bluetooth (BT) – LTE – WLAN

Peak Spectrum of WLAN Test Signal

Recieved WLAN Constellation, no interference.

Recieved WLAN EVM Spectrum with no Interfering signal

Interfering signal spectrums (with 20 MHz WLAN at center frequency = GHz)

Interfering Signal 1: CW AM Signal Parameters: – Center Frequency = 2.41 GHz (within, but off center, of WLAN band) – AM Modulation: 1 kHz and 80% (as in IEC , Annex A) – Power level = -10 dBm WLAN does not fail RMS EVM of approx. -23 dBm (by inspection) as an instant average over all subcarriers

Recieved WLAN Constellation from Interfering Signal 1

Recieved WLAN EVM spectrum from Interfering Signal 1

Interfering Signal 2: Bluetooth Parameters – Power Level = -10 dBm – Center Frequency = 2.41 GHz (same as Signal 1) – Max Payload length, Carrier Burst WLAN intermittently fails as a result of the BT signal RMS EVM of WLAN is regularly about -50 dBm (by inspection), with short periods of Higher EVM (at failure) – Consistently much lower EVM from signal 1

Received WLAN Constellation with Interfering Signal 2, WLAN Failure

Recieved WLAN EVM Spectrum with Interfering Signal 2, WLAN Failure

Interfering Signal 3: LTE Parameters – Power Level = -10 dBm – Center Frequency = 2.41 GHz – BW = 10 MHz With these Parameters the WLAN Receiver was never able to establish a link

Interfering Signal 3: LTE Cont. Highest 10 MHz LTE power that allowed the WLAN system to make a connection was -27 dBm – Consistent EVM of about -25 dBm (by inspection) – Large number of subcarriers are affected (see following EVM plot) by this signal – This is due to the wider bandwidth of LTE compared to Bluetooth or the CW AM signal

Received WLAN Constellation with Interfering Signal 3 (-27 dBm Power)

Recieved WLAN EVM Spectrum with Interfering Signal 3 (-27 dBm Power)

Interfering Signal 4: WLAN The interfering WLAN is on the band nearest the victim: – Power = -30 dBm – Center Frequency = GHz – BW = 20 MHz -30 dBm interference power setting was the highest that allowed consistent victim connection Consistent average RMS EVM of about –29 dBm (from inspection)

Recieved WLAN Constellation from Interfering Signal 4

Recieved WLAN EVM spectrum from Interfering Signal 4

Backup Slides

Received WLAN Constellation with Interfering Signal 2, No WLAN Failure

Recieved WLAN EVM Spectrum with Interfering Signal 2, no WLAN Failure

Peak Spectrum Comparison of CW AM, Bluetooth, and LTE from Tests