Wireless is Good - and Complicated

 My Smart Bike is Wireless!

Wireless connectivity is ubiquitous. Most of the time we can take it for granted. That changes when we see dropped connections and spotty Zwift performance.

If you are having wireless issues, it's good to ask: Is something causing interference? When looking my SB20 smart bike setup, I realized that a typical riding session is fairly intense in terms of wireless protocols, bandwidth and data transfer rates. Interference from just my devices is a possibility.

16 Wireless Connections and Counting

Here's the view from my smart bike saddle: two iPads, iPhone, Garmin bike computer, two Zwift play controllers, Heart Rate Monitor (HRM), power meter cranks plus wireless earbuds for an occasional Discord session. Collectively, these devices use 3 different protocol families: WiFi, Bluetooth and Ant+. Most share the same 2.4 GHz frequency spectrum. At last count: One indoor ride uses up to 16 wireless connections.  Add to that, family members in my house use WiFi on their cellphones, while accessing the Internet and streaming media. 

Zwift

Here's what my Zwift riding session looks like. 

Here's a summary of each wireless connection.

Connection	Type	Includes Data for	Direction	Description	Data Volume	5 GHz Capable	Usage / Update	Results
1	ANT+	Power	Right crank to left crank	Power and cadence data for the right crank	Low		Once a second.
2	ANT+	Power	Left crank to smart bike	Consolidated power and cadence data for both cranks	Low
3	ANT+	Power	Left crank to bike computer	Consolidated power and cadence data for both cranks	Low
4	ANT+	Bike Simulation	Smart bike to bike computer	Comprehensive data packet providing power, cadence, speed and distance data.	Low
5	ANT+	Heart Rate	HRM to bike computer	Heart rate	Low
6	Bluetooth	Bike Control	Zwift app to smart bike	Set bike parameters for rolling resistance, slope (inclination), wind and surface type so the bike can set its internally calculated resistance. Can also set Erg mode for a given power target.	Medium ⭐️		Sent by Zwift as needed.	Bike resistance changes.
		Bike Simulation	Smart bike to Zwift app	Comprehensive data packet providing power, cadence, speed and distance data.	Medium ⭐️		Once a second.
7	Bluetooth	Bike Control	Smart bike app to smart bike	Set bike parameters for app simulations and erg workouts. Do crank calibration (zero reset). Enter listen only (external) mode where this app only receives data and another app, like Zwift, controls the smart bike.	Low		Sent by Zwift as needed.	Bike mode or resistance changes; Cranks are calibrated.
		Bike Simulation	Smart bike to smart bike app	Comprehensive data packet providing power, cadence, speed and distance data. Can also include proprietary data like current virtual gear.	Medium		Once a second.
8	Bluetooth	Power	Left crank to Zwift app	Consolidated power and cadence data for both cranks	Low		Once a second.
9	Bluetooth	Zwift Play Control	Left control to Zwift app	Proprietary data for Zwift Play Controller button presses.	Very low		Controller button pressed.	Zwift app executes  action
10	Bluetooth		Right Control to Zwift app
11	Bluetooth	Heart Rate	HRM to Zwift app	Heart rate	Low		Once a second.
12	Bluetooth	Audio	Bi-directional link between Discord app and wireless ear bud/headphones	Audio data: talk and listen	High		Continuous
13	WiFi	Zwift Data	Bi-directional link between Zwift app and Zwift web services	Zwift Avatar / simulation rendering, button press processing, bike data relay and everything else needed by Zwift to display app content is transferred over this WiFi connection to and from Zwift web services.	High ⭐️	Yes	Continuous	Zwift app updates; bike is controlled as needed.
14	WiFi	Zwift Data	Bi-directional Zwift Companion app data and control	Synchronizes the companion and main app with Zwift web services. Handles button presses and other features implemented in the companion app.	Medium	Yes	Continuous
15	WiFi	Bike Computer Data	Bi-directional link between bike computer and its web services (like Garmin connect)	Synchronizes the bike computer with its web services. Handles workout uploads and configuration changes.	Low to Medium		Continuous	Bike computer and related services updated as needed.
16	WiFi	Discord Data	Bi-directional Audio link	Audio chat app: talk and listen	High	Yes	Continuous
	Other Devices to Watch for
	WiFi 🔌	Apple TV (can replace iPad)	Web connection	Content display and streaming	High ⭐️	Yes	Continuous	Can replace #13 above
	WiFi 🔌	TV	Web connection	Content display and streaming	Very High	Yes	Continuous
	WiFi 🔌	PC/Mac Computer (instead of iPad)	Zwift Data	Zwift Avatar / simulation rendering Same as #13 above	High ⭐️	Yes	Continuous	Replaces #13 above
	🔌 = Supports wired Ethernet connection       ⭐️ = Critical data connection

I have to admit, there are more wireless connections than I expected. Indoor riding is not as simple as the brochure says 🤣. 

Tips for Improving your Indoor Rides

• Get a 5GHz router: Using the 5 GHz WiFi band, for devices that support it, will help alleviate congestion in the more common 2.4 GHz frequency band. Optimal placement: 5 GHz access points generally need line-of-sight positioning for best performance. 
• Don't worry about ANT+ connections.  As the table shows, they are low band-width. ANT + usage of the 2.4 GHz band is on par with Bluetooth. Ant+ and Bluetooth usually suffer when then are too many high bandwidth WiFi devices nearby.    
• Turn off unused devices. This includes set-top boxes, cellphones, cordless phones, microwave ovens, baby monitors, smart watches and wireless speakers.
• Use 🔌 direct-wired Ethernet for devices where possible - especially for connections shown in the table above as High Data Volume and ⭐️ critical. Also look for nearby Smart TVs and streaming boxes.  Direct connections for these devices will make a difference.

Want to learn more?  See my post on Indoor Riding - ANT+ and Bluetooth.