RF front end power control for low power RF devices

1. A wireless camera system, comprising:

a plurality of battery-powered, wireless node cameras, each node camera comprising an image sensor for capturing image data, a radio unit for performing wireless communications, at least one processing unit for controlling the image sensor and radio unit, and at least one battery; and

an access point configured to communicate wirelessly with each of the node cameras, and further configured to communicate with a control center that communicatively couples the access point to a computer network,

wherein the radio unit in each node camera, comprises:

a signal processing unit configured to perform one or more wireless protocol processing functions,

a radio-frequency (RF) front end unit coupled to the signal processing unit,

a power unit that completely powers down the RF front end unit when the signal processing unit is in a sleep mode, and powers up the RF front end unit at a predetermined time before an anticipated reception of a beacon signal from the access point, and

a second processing unit coupled to the signal processing unit, wherein prior to entering the sleep mode, the signal processing unit is configured to store its state information in a memory of the second processing unit and upon being awakened from the sleep state the signal processing unit retrieves the state information from the second processing unit and resumes a previous state in accordance with the stored state information.

2. The wireless camera system of claim 1 , wherein the predetermined time is a predetermined amount of time before the end of a delivery traffic information map (DTIM) interval.

3. The wireless camera system of claim 1 , wherein the signal processing unit comprises a WiFi unit and the one or more wireless protocol processing functions comprise one or more functions required by one or more 802.11 standard protocols.

4. A battery-powered, wireless camera comprising:

an image sensor for capturing image data;

a radio unit for performing wireless communications with at least one external device;

a processor for controlling the image sensor and radio unit; and

at least one battery for supplying power to the wireless camera,

wherein the radio unit comprises:

a signal processing unit configured to perform one or more wireless protocol processing functions,

a radio-frequency (RF) front end unit coupled to the signal processing unit,

a power unit that completely powers down the RF front end unit when the signal processing unit is in a sleep mode, and powers up the RF front end unit at a predetermined time before an anticipated reception of a beacon signal from the access point, and

a second processing unit coupled to the signal processing unit, wherein prior to entering the sleep mode, the signal processing unit is configured to store its state information in a memory of the second processing unit and upon being awakened from the sleep state the signal processing unit retrieves the state information from the second processing unit and resumes a previous state in accordance with the stored state information.

5. The battery-powered, wireless camera of claim 4 , wherein the predetermined time is a predetermined amount of time before the end of delivery traffic information map (DTIM) interval.

6. The battery-powered, wireless camera of claim 4 , wherein the signal processing unit comprises a WiFi unit and the one or more wireless protocol processing functions comprise one or more functions required by one or more 802.11 standard protocols.

7. A radio unit contained within a housing of a wireless communication device or system, the radio unit comprising:

a signal processing unit for performing one or more wireless protocol processing functions;

a radio-frequency (RF) front end unit coupled to the signal processing unit;

a power unit coupled to the RF front end unit, wherein the power unit completely powers down the RF front end unit when the signal processing unit is in a sleep mode, and powers up the RF front end unit at a predetermined time before an anticipated reception of a RF signal transmitted by an external device, and

a second processing unit coupled to the signal processing unit, wherein prior to entering the sleep mode, the signal processing unit is configured to store its state information in a memory of the second processing unit and upon being awakened from the sleep state the signal processing unit retrieves the state information from the second processing unit and resumes a previous state in accordance with the stored state information.

8. The radio unit of claim 7 , wherein the predetermined time is a predetermined amount of time before the end of delivery traffic information map (DTIM) interval.

9. The radio unit of claim 7 , wherein the signal processing unit comprises a WiFi unit and the one or more wireless protocol processing functions comprise one or more functions required by one or more 802.11 standard protocols.