Wireless Communication System Hidden Terminal Mitigation
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Solution Overview
Problem
In wireless communication systems using unlicensed bands, the hidden terminal problem leads to reduced throughput due to collisions and inefficient resource utilization, especially in environments with high traffic and multiple nodes competing for the same resources, where the RTS/CTS mechanism is ineffective in ensuring accurate transmission opportunities.
Innovation Solution
A wireless communication system that employs a secondary frequency band for communication between access points and stations, using a UD report to transfer information about transmission-waiting user data, allowing the receiving node to set a fixed transmission prohibition time and grant transmission opportunities to the transmitting node, thereby reducing the impact of hidden terminals and improving resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTS/CTS mechanism is used to solve hidden terminal problem, then transmission opportunity is obtained, but throughput is reduced due to collisions and inefficient resource utilization in high traffic environments
Solution Approach 1:
The patent implements a feedback mechanism where the receiving node sends back a transmission opportunity grant confirmation to the transmitting node. This feedback loop ensures that the transmitting node only transmits when the receiving node has actually obtained and granted the transmission opportunity, eliminating unnecessary transmissions and improving throughput while maintaining reliable transmission opportunity acquisition.
Solution Approach 2:
The patent requires the receiving node to perform preliminary actions by obtaining the transmission opportunity from the channel access control unit before granting it to the transmitting node. This preliminary action ensures that the transmission opportunity is properly secured from hidden terminals before the actual data transmission begins, preventing collisions and improving resource utilization efficiency.
2Adaptability or versatility
If random access scheme is used in unlicensed band, then wireless communication is enabled, but hidden terminal problem causes reduced throughput and resource wastage
Solution Approach 1:
The patent introduces a channel access control unit as an intermediary between the transmitting and receiving nodes. This intermediary manages the transmission opportunities and coordinates the RTS/CTS exchange, ensuring that hidden terminals are properly accounted for and that transmission opportunities are allocated efficiently, thereby improving throughput while maintaining wireless communication capability.
Solution Approach 2:
The receiving node performs preliminary action by obtaining the transmission opportunity from the channel access control unit before initiating the RTS/CTS exchange with the transmitting node. This ensures that the transmission opportunity is securely obtained from potential hidden terminals before being granted to the transmitting node, preventing resource wastage and improving overall throughput.
3Productivity
If transmission opportunity is obtained without UD report, then communication starts, but resource wastage occurs when no user data is present
Solution Approach 1:
The patent uses the UD report as a feedback mechanism that informs the receiving node about the presence of user data at the transmitting node. The receiving node uses this feedback information to make an informed decision about whether to proceed with obtaining and granting transmission opportunities, thereby avoiding resource wastage when no user data is present while maintaining efficient communication when data is available.
Data Source
AI summary
A wireless user equipment performing wireless communication in a primary and a secondary frequency bands, a first wireless access point AP performing the wireless communication in the primary frequency band, and a second wireless base transceiver station BTS performing the wireless communication in the secondary frequency band are included. The AP and the BTS are connected to each other through a network. A UD report transfer unit transfers a UD report including information relating to transmission-waiting user data destined for a receiving node. The receiving node includes a transmission opportunity control unit which sets a fixed transmission prohibition time in a channel in the primary frequency band for a wireless communication device in a vicinity, obtains a transmission opportunity, grants the transmission opportunity to the transmitting node, and causes the user data to be transmitted from the transmitting node according to the transferred UD report.