Power management and security for wireless modules in “machine-to-machine” communications

What is this patent about?

’550 is related to the field of machine-to-machine (M2M) communications, specifically addressing the power management and security challenges inherent in remote monitoring systems. In typical wireless wide area networks, devices are optimized for mobile handsets that remain idle but active to receive calls, a behavior that rapidly depletes the batteries of remote sensors. The invention seeks to bridge the gap between standard cellular protocols and the extreme energy efficiency required for long-term autonomous operation of remote units.

The underlying idea behind ’550 is to minimize the radio resource control (RRC) tail period by proactively disconnecting the device immediately after a data exchange is complete. Rather than waiting for the network to time out and issue a release command—which can take several seconds of high power consumption—the device initiates a shutdown sequence the moment it receives a server response. This approach treats the cellular connection as a transient event rather than a persistent state, significantly extending battery life by bypassing standard inactivity timers.

The claims of ’550 focus on a specific sequence of operations where a wireless module wakes from a sleep state, establishes a 4G RRC_CONNECTED state, and exchanges a single pair of UDP-based messages. Crucially, the independent claims cover the module sending a detach message or transitioning to a radio-off state after receiving a response but before the network can trigger a radio bearer reconfiguration or a standard connection release. This sequence must occur before the device enters a discontinuous reception (DRX) state, ensuring the radio is active for the absolute minimum time necessary.

In practice, the invention utilizes a connectionless communication model, preferably using UDP or UDP Lite to avoid the multi-packet overhead of a TCP handshake. To maintain high security without the energy cost of multiple round-trip authentications, the module includes a digital signature and encrypted sensor data within the initial uplink packet. This allows the server to authenticate the device and decrypt the payload in one step, enabling the device to receive a single encrypted response and immediately power down both the radio and the processor.

This approach differentiates itself from prior art by aggressively managing the transition between active and dormant states at the device level rather than the network level. By utilizing Public Key Infrastructure (PKI) with Elliptic Curve Cryptography (ECC), the system achieves robust security with shorter keys, reducing the amount of data transmitted. The combination of proactive detaching and efficient cryptographic signatures allows the module to remain in a deep sleep for the vast majority of its operational life, only consuming significant power for a fraction of a second during data bursts.