Noise Interference; Antenna Orientation - Infineon AIROC CYW20829 Bluetooth LE SoC Manual

r e s t r i c t e d
Achieving long range transmission using AIROC™ CYW20829
Bluetooth® LE SoC
Testing and results
5.2

Noise interference

Noise and interference are the largest contributors to poor range in a long-range testing environment. In the
real world, increased noise means your Bluetooth® devices may disconnect at ranges far shorter than
advertised. To improve SNR, it is important to reduce the noise and interference during testing. To reduce
interference, make sure to test in the morning and walk away from people to reduce the impact of noise.
Maintain a line of sight, or LoS, connection between the peripheral and central devices at all times.
People often carry multiple devices that operate on the 2.4-GHz band, such as their smartphones,
smartwatches, and wireless earbuds. Just as a building's walls may inhibit Bluetooth® range, other physical
objects, such as beach umbrellas or lifeguard towers, also contribute to multipath, and may absorb radio
frequency energy. Multipath occurs when radio signals propagate between two antennas via multiplate paths.
Multipath is undesirable, as it can lead to interference and distortion of a wanted signal. In the real world, LoS
between devices may not be plausible. We actively monitored the Received Signal Strength Indicator (RSSI), of
the receiver and adjusted the walking path along the beach during testing to keep the RSSI higher than the
maximum S8 Coded PHY sensitivity. The maximum output power of the CYW20829 MCU is 10 dBm using the
internal power amplifier, and the Coded PHY helps to improve the maximum sensitivity of to -106 dBm. The
Link budget is the sum of the absolute value of all gains and losses of a radio frequency system in decibels. In
an ideal environment, the maximum link budget is |10 dBm| output power + |-106 dBm| sensitivity = 116 dB.
5.3

Antenna orientation

Antenna directivity is a measure of the amount of radiated energy moving in a particular direction, while
antenna gain takes both an antenna's directivity and efficiency. Antennas do not radiate with the same power
in all directions, as shown in
antenna gain of the CYW920829M2EVK-02 kit is measured.. Different Bluetooth® antenna radiate most optimally
in different directions, which influence the directions in which the boards face during testing. Since the
directivity of an antenna when transmitting is identical to the directivity of an antenna when receiving, both the
boards were placed facing each other, taking into consideration the maximum antenna gain (see Figure 6). The
CYW920829M2EVK-02 kit is considered a "directional" antenna, as the radiation pattern is strongest in one
particular angular direction.
Figure 11 Board antenna orientation
Application note
Figure 11. To determine the directions in which the kit radiates the strongest, the
13 002-38518 Rev. **
2023-09-12