BLE peripheral device supporting multiple connections from central devices

[Anonymous]

Hi,

I'm working on a usecase that shall meet the following conditions:
1. BLE device shall operate in peripheral mode.
2. BLE device shall support multiple connections from other central devices. If yes; how many connection can i have?
3. Is there Linux driver/stack available for the BLE chipset?

Is there any chipset available which supports the same?
Please advice...

[Anonymous · Accepted solution]

1. Easy to do

2. Only one connection can be open at a time, thus to support multiple connections you would need multiple chips, time-multiplexed connection cycling, or a newer chip that can support multiple connections at a time. See the PSoC 6 as the new chip-set that supports more connections: PSoC 6 MCU with Bluetooth Low Energy (BLE) Connectivity FAQ – KBA220700

3. As for linux support, see this thread: BLE for linux to use with PSOC BLE (tl;dr; Not supported, but possible)

The PSoC 6 is the chip you would want to use for multiple BLE connections.

[Anonymous]

Thanks e.pratt_1639216 for the quick and accurate response.
Definitely, PSoC6 suits to my need but as the reference says; the connection limit is 4 and I need more than 5; at least 5.
Could you please guide me based on the following:
1. What is the limiting factor for the same(no: of connections)?

2. My usecase is like receive and transmit bulk data(up to 1MB) over BLE as notification(with 3 custom service characteristics) and send to a master processor(running linux) for further processing(plan is to use UART) and retransmit to other BLE devices. In Notification packet; how much payload i can add? 20bytes or will it support more?

[Anonymous]

If you are looking for more than 5 simultaneous connections, I suggest you take a look at the WICED BT/BLE solution that Cypress provides. The CYW20706 supports more than 5 simultaneous connections.

1. What is the limiting factor for the same(no: of connections)?

Usually the PHY and LL design and memory would determine the max number of connections a device can support.

2. If you have multiple connections, you won't be able to achieve high transfer rates because the peripheral will have to atleast send empty packets to other connected peer devices.

You can increase the payload of the notification length to ATT_MTU-3. However, if you don't have Bluetooth 4.2 DLE enabled, then the data would be sent over different packets (20 bytes in each packet).

[Anonymous]

Thanks for your valuable feedback and suggestion.
Will consider the WICED solution you mentioned.

[Anonymous]

I would assume that "Maximum of 100 LE Connections" means 100 BLE connections? If so, then that is indeed a fantastic choice for more simultaneous connections