Receiver Minimum Input Sensitivity in WiFi 7 (IEEE 802.11be)

In Wi-Fi 7 (IEEE 802.11be), receiver minimum input sensitivity is a critical parameter that defines the lowest power level at which a receiver can successfully decode a signal while maintaining a specified performance level. This parameter ensures that Wi-Fi 7 devices can operate effectively even when the received signal strength is low, which is essential for maintaining connectivity in challenging conditions such as long distances or environments with significant interference.

Minimum input sensitivity refers to the lowest signal strength at which the receiver can reliably detect and demodulate the incoming signal with an acceptable level of error. It is specified in terms of received power in dBm and varies based on channel bandwidth, modulation and coding schemes.

Key Points of Receiver Minimum Input Sensitivity in Wi-Fi 7

• Definition: Minimum input sensitivity is the threshold received power level, measured in dBm, at which the receiver must achieve a specific performance criterion, typically expressed in terms of packet error rate (PER) or bit error rate (BER).

• Dependence on Modulation and Coding Schemes: The sensitivity requirement changes with the modulation and coding rate used. Higher order modulations (e.g., 4096-QAM) require stronger signals to maintain the same performance level as lower-order modulations (e.g., BPSK or QPSK).

• Channel Bandwidths: Wi-Fi 7 supports multiple channel bandwidths (20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz). Sensitivity requirements are defined for each bandwidth because wider channels collect more noise and interference, which can affect sensitivity.

Typical Sensitivity Values:

• For a 20 MHz Channel: The minimum input sensitivity might range from around -82 dBm for BPSK with 1/2 coding rate to about -46 dBm for 4096-QAM with 5/6 coding rate.

• For a 160 MHz Channel: Sensitivity values would typically be higher (less negative) due to the wider bandwidth, ranging from about -73 dBm to -37 dBm for similar modulation and coding rate combinations as above.

• For a 320 MHz Channel: The requirements will be slightly less stringent due to even more bandwidth, but the exact values are defined in the standard for specific use cases. The same have been mentioned in the following table.

Performance Criteria:

Wi-Fi 7 usually specifies that the receiver must achieve a Packet Error Rate (PER) of 10% or better at the defined sensitivity level. This means that only 1 out of 10 packets can be erroneously received at the sensitivity threshold.

Factors Affecting Sensitivity:

• Noise Figure: The internal noise of the receiver circuitry affects sensitivity; lower noise figures lead to better sensitivity.

• Signal Processing: Advanced signal processing techniques, such as MIMO (Multiple Input Multiple Output) and beamforming, can enhance effective sensitivity by improving signal quality.

• Channel Conditions: Real-world factors like interference, multipath propagation and fading can impact the receiver’s ability to meet the sensitivity requirements.

Testing and Compliance:

Receivers are tested by transmitting signals at various power levels and measuring the resulting PER or BER. The minimum power level at which the receiver can maintain the required performance is recorded as the sensitivity. Tests are conducted across the supported bandwidths, modulation schemes, and coding rates to ensure compliance with the standard.

Example of Sensitivity Requirements

1. For a 20 MHz channel using 64-QAM modulation with a 3/4 coding rate, Wi-Fi 7 may specify a minimum input sensitivity of around -65 dBm. This means the receiver must correctly decode the signal with a PER of 10% or better when the received power is -65 dBm.

2. For a 320 MHz channel using 4096-QAM 3/4, the minimum input sensitivity requirement might be around -37 dBm, reflecting the challenges of maintaining performance with high data rates and wide bandwidths.

Importance of Minimum Input Sensitivity

• Range and Coverage: Better sensitivity allows devices to maintain connections at greater distances from the access point, improving overall network coverage.

• Performance in Noisy Environments: High sensitivity ensures reliable connections even in environments with high levels of interference or noise.

• Power Efficiency: Devices with good sensitivity require less transmission power to maintain a link, which can be beneficial for battery operated devices.

In summary, the receiver minimum input sensitivity defined in IEEE 802.11be for Wi-Fi 7 ensures that devices can operate efficiently even under low signal conditions, supporting the high performance and extended range capabilities expected of the latest Wi-Fi technology.