Getting ZigBee and WiFi to play nice
GreenPeak's just-announced GP501 chip allows ZigBee, WiFi and Bluetooth to work side-by-side in the one device using what GreenPeak calls a sophisticated coexistence scheme.
WiFi and ZigBee both operate in the public 2.4 GHz band and as homes and offices become increasingly saturated with WiFi signal there clearly has to be some way of making WiFi play nice with other radio technologies - such as ZigBee - since interference will become a problem as homes are populated with more WiFi-communicating settop boxes, smartphones, tablets, home security and so on; in addition to the low-powered ZigBee connected 'things' (meters, fridges, washing machines and everything else the imagination can conjure up).
GreenPeak's silicon solution is to implement a 'coexistence' interface in its ZigBee chip so that different radio technology chips can be sited side-by-side in a single device and operate simultaneously. They do this by arbitrating over the shared frequency to prevent contention, signal degradation and data loss.
GreenPeak also claims it has implemented Deep Packet Inspection enabling advanced packet management and allowing the host processor to go into a "deep-sleep" mode to conserve power.
"While most other ZigBee transceiver chips only include a superficial inspection of the MAC and PHY headers, the GP501 looks beyond these layers and executes a Deep Packet Inspection and, based on the outcome, the chip can decide if the packet has to be passed on to the higher layer application or can be ignored," says the press release. "The DPI engine is also security aware, blocking unauthorized packets without involving the host processor and ensuring the system does not waste energy analyzing non-compliant packets. The DPI feature can be used for Wake-on-LAN functionality, where ultra-low power ZigBee is used to wake up the main processor from its sleep mode to enable Wi-Fi networking."