Increasing the data packet without DLE as my central device uses BLE v4.1

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

Einar Thorsrud — Mon, 27 Aug 2018 08:01:23 GMT

Yes, that is correct.

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

bale11 — Sat, 25 Aug 2018 04:45:54 GMT

Okay so, the maximum packet size depends on the maximum size of the link packet (physical layer packet) which we can extend by using DLE right ?

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

Einar Thorsrud — Fri, 24 Aug 2018 12:31:12 GMT

Hi,

Yes. It might be possible to send 10 packets, but it depend on the peer device as well. As I said, there is no definitive limit so you basically just have to test, and the result you get are really just valid for the peers you have tested with as the capabilities of different devices vary greatly.

The size of the packet could be anything within the maximum configured size and the maximum size for that link. The buffer is scaled for packets of the largest size (think of it as a buffer of packet "slots").

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

bale11 — Fri, 24 Aug 2018 12:10:22 GMT

So you mean to say that number of packets depends on the number I define in this variable :

ble_cfg.conn_cfg.params.gatts_conn_cfg.hvn_tx_queue_size = 10;

Here I should be able to send 10 packets right ?

Also what will be the size of this packet? Will it be equal to the size set in the DLE packet size?

P.S I only have one development board with me so I cant really use nrf sniffer. I already ordered one more board, I will send you the screenshots ASAP when i get another nrf board.

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

Einar Thorsrud — Fri, 24 Aug 2018 11:59:57 GMT

There is no definitive restriction of 6 packets per connection in the BLE spec nor in the SoftDevice. It depends on the length of the connection event and that the SoftDevice has data to send. Generally, you will get the maximum amount of packets if you have enough memory (TX buffer), so that there is data ready to send. (Even with the older SoftDevice where you could set 1, 3 or 6 as buffer length, you could sometimes get 7 packets per connection if the application was able to write a new packet to the SoftDevice in time.)

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

bale11 — Fri, 24 Aug 2018 09:31:09 GMT

Htc one m9 (my central device) doesn't support more than one packet. Could also tell me if I'm correct about point 2) , which is "Maximum number of packets that can be sent is 6, even for BLE v4.2 and this is by default set to 6 packets by the softdevice S132 v6"

RE: Increasing the data packet without DLE as my central device uses BLE v4.1

Einar Thorsrud — Fri, 24 Aug 2018 09:24:48 GMT

Hi,

It seems impossible that long packets (DLE) would works as it is not supported by the central, so the only option would be to use multiple packets per connection event hoping that that is supported. From the nRF side this should be OK as long as you have increased the event length and TX buffer size. Can you record a sniffer trace so that we can see what is happening on air?