How high is the Data Rate?
top It may not be obvious why a simple temperature or intrusion sensor needs to transmit data at 250 Kbps (at 2.4 GHz) or even 20 Kbps (at 868 MHz), but the reason becomes clear when you consider the need to prolong battery life. Even when the sensor is transmitting only a few bits or bytes, the system can be more efficient if it transmits and receives the data quickly. For instance, a 0.5 mW transmitter consumes many milliwatts whether its transmitting 100 or 100,000 bps. For any given quantity of data, transmitting at a higher data rate allows the system to shut down the transmitter and receiver more quickly, saving significant power. Higher data rates at a given power level mean theres less energy per transmitted bit, which generally implies reduced range. But both 802.15.4 and ZigBee value battery life more than raw range and provide mechanisms to improve range while always concentrating on battery life. What is the Data Latency for ZigBee Networks? top Sensor systems have a broad
