RSU Spatial Filtering for V2V Message Recovery
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Solution Overview
Problem
In vehicle-to-vehicle (V2V) communication systems, vehicles with non-line-of-sight (NLOS) conditions due to obstructions like buildings often fail to receive basic safety messages (BSMs), leading to potential accidents and inefficiencies in message transmission, as RSUs with omnidirectional antennas struggle to recover and retransmit overlapping BSMs effectively.
Innovation Solution
The implementation of a road side unit (RSU) with two omni-antennas and a signal processor that performs spatial filtering to generate directional beam-patterns for receiving and retransmitting BSMs, using weighting vectors to separate and retransmit messages between vehicles with NLOS, employing techniques like XOR operations and beamforming to ensure message delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If omnidirectional antennas are used in RSU, then message coverage area is improved, but message recovery reliability deteriorates due to overlapping signals from multiple vehicles
Solution Approach 1:
The patent segments the omnidirectional signal reception into multiple directional beam-patterns. The signal processor divides the received omnidirectional signals from multiple vehicles into separate directional beams, each targeting a specific vehicle pair. This segmentation allows the system to maintain omnidirectional coverage while recovering individual messages reliably by processing each directional component separately.
Solution Approach 2:
The patent applies local quality by creating direction-specific processing paths within the RSU. Each directional beam-pattern is processed with specific weighting vectors tailored to that direction's characteristics. This allows the system to optimize message recovery for each spatial direction independently, improving reliability for specific vehicle pairs while maintaining overall omnidirectional coverage.
2Device complexity
If conventional RSU with omni-antennas is used, then device complexity is reduced, but productivity in message transmission deteriorates due to packet collisions
Solution Approach 1:
The patent introduces an intermediary signal processor that acts as a mediator between the omnidirectional antennas and the message recovery process. This intermediary component performs spatial filtering and directional beam-pattern generation, enabling the system to resolve packet collisions without requiring complex antenna arrays. The intermediary processor adds intelligence to the transmission system, improving productivity while keeping the antenna structure simple.
3Reliability
If spatial filtering with directional beam-patterns is implemented, then message recovery reliability is improved, but device complexity increases due to signal processing requirements
Solution Approach 1:
The patent implements dynamic signal processing where the signal processor adaptively generates directional beam-patterns based on the spatial distribution of transmitting vehicles. The weighting vectors are dynamically adjusted according to the received signals' characteristics and spatial positions. This dynamic approach allows the system to maintain high reliability while optimizing processing complexity by adapting to real-time conditions rather than using fixed complex processing structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient recovery and retransmission of BSMs between vehicles with NLOS, reducing packet collisions and ensuring that all vehicles receive critical safety information, thereby enhancing safety and communication efficiency in V2V systems.
Implementation Method 1
a signal processor that performs spatial filtering to recover (i) a first message from the first and second RX signals using a first directional beam-pattern and (ii) a second message from the first and second RX signals using a second directional beam-pattern
Implementation Method 2
a signal processor that performs spatial filtering to recover (i) a first message from the first and second RX signals using a first directional beam-pattern
Data Source
AI summary
In a vehicle-to-vehicle communication system, an intersection-located road side unit (RSU) having two omni-antennas applies spatial filtering to the antennas' RX signals to recover first and second overlapping basic safety messages (BSMs) concurrently transmitted by two intersection-approaching vehicles that have no direct line of sight (NLOS) between them. The RSU retransmits each BSM for receipt by the other vehicle using either an omnidirectional retransmission technique in which the two messages are sequentially transmitted using an omnidirectional beam-pattern, a directional retransmission technique in which the two messages are sequentially transmitted using directional beam-patterns, or an XOR retransmission technique in which the RSU applies an XOR operation to the two BSMs and transmits the resulting XOR message using an omnidirectional beam-pattern. A receiving vehicle can apply an XOR operation to the XOR message and a local copy of the first BSM message to recover the second BSM message.