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CC1310: combine multiple CC1310 into a transmitting-only multichannel broadcasting system

Ma Tianfu
Prodigy 110 points
Part Number: CC1310

I need a sub 1GHz broadcasting system. One transmitter to at most 20 receivers. Each receiver need around 100kbps data rate. And when all receivers are working at the same time, a single channel is not enough.

So I wonder whether I can use multiple CC1310 chips, maybe 4 to 8 pieces, "ganged" together. Each chip works at a separate channel. Using a rf mixer to mix all outputs to a single antenna. Is this possible? is there any ti reference design working in this way? Or you recommend using a separate antenna for each chip? I'd also like to know other pitfalls when using multiple CC1310 in a single board, particularly rf interference. Power consumption is not a concern for us. Shed me some light. Not quite familiar with sub 1GHz radio.

  • +1
    TI__Mastermind 33080 points

    Hi,

    Most designs from a single-point to multi-points do not transmit/receive at the exact same time. If transmission or receiving can occur at exactly the same time, then this needs to be take into account when considering the link budget since one radio solution can affect the other when positioned on the same board or positioned close-by. By using multiple antennas on one board there will be a greater isolation between the two radios. The isolation between the two antennas will be roughly 10-20 dBs. If there is a common antenna then this antenna isolation will be reduced to 0 dB. 

    If one radio on the board is transmitting, and the other radio is receiving on the same board; the practical sensitivity limit of the receiving radio will be impacted by the level of RF entering from the radio transmitting on the same board. The receiving radio can filter out a certain degree of disturbance (selectivity / blocking) pending on the frequency delta between the two radios.  

    For example, if the disturbance (other radio channel) is 2 MHz away, with a 50 kbps PHY, the blocking characteristics is 60 dB. If we have two antennas and an antenna isolation of 10 dB; then there will be 70 dB of blocking. If the sensitivity is typically -110 dBm, then during a 14 dBm Tx burst on radio 1, radio 2 sensitivity will fall from -110 dBm to -56 dBm which will have a huge impact on the range. 

  • 0 in reply to RGW
    Prodigy 110 points

    Thank you so much for such a detailed reply. Now I understood that separate antennas for each chip are better in isolation and simultaneous transmitting and receiving should be avoided as possible as we can.