What are limitation of combo Wi-Fi / BLE modules (coexisting on one chip, concurrent communication) VS classical Wi-Fi and/or BLE chips?
Thanks in advance!
I have done some research on this topic. I will put here my findings in case someone else have the same question.
My primary concern was about Wifi / BLE modules limitations, since these two communications are in same band (2.4GHz) running on the same chip on same antenna.
Much to my surprise there is no big problems with this modules.
- Since both Bluetooth and Wi-Fi are using same wireless band (2.4GHz), their transmissions can interfere with each other. This have impact on performance and reliability of both wireless interfaces.
-There are several methods to reduce this interference:
--Temporal Isolation: Time Division Multiplexing (TDM) - method where BT and Wi-Fi radios take turns transmitting.
--Spatial isolation: Involves placing BT and Wi-Fi radios (and their antennas) as far apart as possible and, when possible, placing insulating material. between them. Impossible with combination BT/Wi/Fi modules.
--Frequency Isolation: Adaptive Frequency Hopping (AFH) - feature found in most BT devices today. BT radio scans the operating band for interference and adapts its frequency hopping patterns to avoid channels used by Wi-Fi.
-Dual Wi-Fi/BT chips use above methods to reduce interference. Additionally there is Collaborative Mechanisms: BT and the Wi-Fi radio "time slice" (only one transmits at a time). Radios exchange information regarding their transmitting status using hardware connections between the radios. The most common implementations are (IEEE 802.15.2 Coexistence Compliance): Two-Wire and Three-Wire coexistence.
-Except apparent time delays in executing commands because “Time Slicing”, there is no known issues.
*Furthermore, nowadays there are multiprotocol modules that incorporates Wi-Fi/Thread/ZigBee/BT on same chip. What a time to be alive! :D
Thanks for sharing, very interesting.
Are there any particular modules that you can recommend that also have good developer support?