Low delay wireless transceiver module

[nixmd]

I am looking for a low delay wireless module which can send and receive data in a very short time.
Data length is just a few bytes generated by a microcontroller connected by UART/SPI interface.
The application requires repetitive send and receive of data in less than 10ms, which means time required to send data and receiving the reply from the second device must not exceed 10ms (repetitively)
I had used RXQ2 wireless module which was a really awesome, but for some reasons I have to find another module which can provide me this requirement.
Do you have any experience in this field? can you suggest me a replacement for RXQ2 with this requirement?

P.S: I have test these modules and none of the could handle this requirement:

nrf24l01
amplified nrf24l01
DRF7020d20
HMTRP
ESP8266MOD (transceiving time was lesser than 10ms but amount of time required by module to be able to accept new buffer of data was much more than 200ms)

 

[KlausST]

Hi,

what´s your baud rate?
What exactely are "a few bytes"? Please tell the maximum.

Klaus

 

[mtwieg]

I've used the nrf24L01 modules in the past to send packets every 1ms, and their latency was much less. Not sure why you found them to be inadequate.

 

[biff44]

a lot of delay is made up acquiring packets/headers, doing error correcting, etc. Also for half duplex, there is a frequency tuning/settling time if tx and rx channels are different.

I would use two separate chips, one transmitting all the time, and one receiving all the time. Make any bandpass filters or baseband filtering have BIG bandwidth, and you will have no trouble at all

 

[nixmd]

Hi,

what´s your baud rate?
What exactely are "a few bytes"? Please tell the maximum.

Klaus

baud rate is not a big deal, but you may consider it 38.4k
same about distance, lesser than 10m

 

[KlausST]

Hi,

I asked about baud rate and frame size because this tells about unavoidable delay time.

With 38400 baud each byte will take about 250us. So just 20 transferred bytes will take 10ms (5ms in one direction, 5ms in the other direction, if my mind calculation is correct)

But you don't say how many bytes....is it a secret?

Klaus

 

[nixmd]

Hi,

I asked about baud rate and frame size because this tells about unavoidable delay time.

With 38400 baud each byte will take about 250us. So just 20 transferred bytes will take 10ms (5ms in one direction, 5ms in the other direction, if my mind calculation is correct)

But you don't say how many bytes....is it a secret?

Klaus

transmitting 4 bytes and receiving 4 bytes.

 

[mtwieg]

With the nrf24l01, each packet has at most 9 bytes of overhead. Even at the lowest datarate of 250ksps, latency should be <2ms. If you use auto acknowledgement on the receiving device, a round trip TX/RX operation should still only be a few milliseconds.