Wireless Device Discovery Using Directional Antennas
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Solution Overview
Problem
In next-generation wireless communication networks operating at higher frequencies, directional antennas are necessary to maintain communication range, but wireless devices must first 'discover' each other's direction to establish a directional link, which is challenging using omnidirectional antenna patterns due to signal attenuation and gain loss.
Innovation Solution
Wireless devices employ an initial omnidirectional antenna pattern for device discovery by repeating the packet preamble sequence and spreading the remainder of the packet, then switch to directional antennas for communication, using a narrowband preamble followed by a wideband signal to compensate for signal gain loss and improve multipath fading immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If directional antennas are used to maintain communication range at high frequencies, then communication range is improved, but device discovery becomes difficult
Solution Approach 1:
The patent segments the communication process into two distinct phases: a device discovery phase using omnidirectional antennas, and a data communication phase using directional antennas. This segmentation allows each phase to use the most appropriate antenna type for its specific function, resolving the contradiction between discovery ease and communication range.
Solution Approach 2:
The patent performs device discovery as a preliminary action before establishing directional communication links. During this preliminary phase, omnidirectional antennas are used to locate and identify other devices. Once discovery is complete, the system transitions to directional antennas for actual data communication, ensuring both easy discovery and maintained communication range.
2Ease of operation
If omnidirectional antenna pattern is used for device discovery, then device discovery is improved, but signal gain is reduced
Solution Approach 1:
The patent segments the antenna operation into two modes: omnidirectional mode for device discovery and directional mode for data communication. During the discovery phase, omnidirectional antennas provide 360-degree coverage enabling easy device location. After discovery, the system switches to directional antennas that concentrate energy in specific directions, restoring signal gain for communication.
Solution Approach 2:
The patent implements periodic switching between omnidirectional and directional antenna patterns. The system periodically uses omnidirectional patterns during discovery phases, then transitions to directional patterns for communication phases. This periodic action allows the system to alternate between the two antenna characteristics as needed, achieving both easy discovery and maintained signal gain.
3Speed
If high frequencies are used for next-generation wireless networks, then data rate is improved, but signal attenuation is increased
Solution Approach 1:
The patent changes the antenna pattern parameter from omnidirectional to directional to compensate for frequency-related attenuation. By using directional antennas with higher gain during the data communication phase, the system counteracts the increased signal attenuation inherent in high-frequency operation, thereby maintaining effective communication range while benefiting from high data rates.
Data Source
AI summary
A wireless device (100) communicates in a wireless network, and executes a wireless device discovery process to discover other wireless devices (100) in the wireless network. In the wireless device discovery process, the wireless device (100) sets its antenna pattern to have an omnidirectional antenna pattern (202), and transmits a first packet (300) using the omnidirectional antenna pattern (202). The first packet (300) comprises a packet preamble sequence (310) formed by repeating each sample of a synchronization sequence N times (N>1). The remainder (320) of the first packet (300) is formed by spreading each sample thereof with a spreading factor P (P>1). For normal data communications, the wireless device (100) sets the antenna pattern to have a directional antenna pattern (204), and transmits a second packet using the directional antenna pattern (204).