System Architecture Design

pSHIELDSystem Architecture Design3.2.1.2.2 IEEE 802.15.4 chips comparisonPUFor WSNs the selection of the radio is a critical for NMPS nodes, because the performance should not beevaluated for a individual NMPS node. The application requirements define what type of radio is needed.A wideband radio operating at 2.4 GHz and comply with IEEE 802.15.4 standard offer advantages thatare important for the pSHIELD scenario. There are several radio modules available in the markets that arein compliant with IEEE802.15.4 standard. Most of the module differences lie on its power profile, deviceinterface and additional features. Several IEEE802.15.4 compliant radio from Atmel, Chipcon, Microchipand MaxStream are listed Table below. When very high data rate are required (depends of the applicationrequirement) AT86RF231 is the best choice. XBEE module from MaxStream has 50 mW output powerand range from 40 m - 1.6 km. The module also provides a complete solution including the antenna.Other radio chip requires a careful design of an external antenna. The USART device interface is veryeasy to configure and XBEE has two modes of operation which are transparent and API mode.AtmelAT86RF231ChipconCC2420MicrochipMRF24J0MAMaxStreamXBEEData rate (kbit/s) 250, 500,250 250 2501000, 2000Rx power (mA) 12.3 19.7 19 50Tx power14/+3 17.4/0 23/0 45(mA/dBm)Power down (µA) 0.02 1 2