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CC1101 Link Budget and current consumption

Meshari Alobaid
Prodigy 80 points
Other Parts Discussed in Thread: CC1101, CC1150

Hi all,

I'm working in a project where I'll be using many transmitters and a single receiver (one way communication) and I'm planning to use CC1101, but I've few questions regarding the chip:

1. I calaculated the link budget for LOS and these are the results I came up with:

    F = 315 MHz, Data rate = 500 kBaud,    Calculated Distance =  7590 m

    F = 433 MHz, Data rate = 250 kBaud,    Calculated Distance =  12348 m

    F = 868 MHz, data rate = 500 kBaud,     Calculated Distance =  4344 m

  I know these are ideal results, but are these values close to the practical results?

2. In CC1101  transmit mode, is there any current consumption whatsoever in the receiving part, if so would you recommend using CC1150 for the transmitter nodes instead?

3. Is CC1101 capable of receivng from mnay nodes, I mean what's the receiving capacity of CC1101?

Tanks in advance

  • 0
    TI__Mastermind 39860 points

    1) You will not achieve the theoretical range you have calculated. Refer to design note DN018 (Range Measurements in an Open Field Environement) for a better model to estimate range.

    As a rule-of-thumb: 120 dB link budget at 433 MHz will give 2 km range. Keeping everyting equal (sensitivity, output power, antenna gain) the range will be reduced by a factor 2 when increasing the frequency by a factor 2. Every 6 dB increasein the link budget will  increase the range by a factor 2.

    2) No RX current in TX mode. Still, for a TX only application you should consider CC1150 for cost reason.

    3) You can only receive from one node at the time. If many nodes are tramsnitting at the same time you will most likely receive nothing (co-channel rejection). You need to use time-division multiplexing, i.e only one traansmitter is on a any given time.

  • 0 in reply to Sverre
    Prodigy 80 points

    First of all, Thanks a lot for the speedy response, I'm really amazed :) ..

    Secondly, could you please elaborate more about the 120 dB link budget. (I mean what is it?, could you define it for me)

    Thanks again

  • 0 in reply to Meshari Alobaid
    TI__Mastermind 39860 points

    Link budget = output power - sensitivity + antenna gain RX + antenna gain TX 

    Example: +10 dBm output power, antenna gain TX = antenna gain Rx = 0 dBi, -95 dBm sensitivity. Link budeget = 10 - (-95) + 0 + 0 = 105 dB.

  • 0 in reply to Sverre
    Prodigy 80 points

    In the last example I think you meant 105 dBm not 105 dB.

    Please correct me if i'm wrong

  • 0 in reply to Meshari Alobaid
    TI__Mastermind 39860 points

    Well, I have to correct you. The link budget is in dB. Sensitivity and output power are in dBm, and antenna gain is expressed in dB.

    Refer also to the to web (e.g Wikipedia). Tons of information available on Link Budget.