Relay Header Control Information Feedback
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Solution Overview
Problem
In wireless communication systems, especially in Machine Type Communication (MTC) networks, uplink-only relaying faces challenges in feeding back control information from relay devices to terminal devices, which hampers efficient data transmission due to the lack of feedback mechanisms for power control and timing synchronization.
Innovation Solution
The introduction of a relay header with control information, such as power control and timing advance information, is added to messages relayed from terminal devices to base stations, allowing the base station to transmit this information back to the terminal devices, enabling them to adjust their transmission parameters accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If uplink-only relaying is used to extend coverage and support low-power MTC devices, then device power consumption is reduced and coverage is extended, but control information feedback from relay to terminal is lost
Solution Approach 1:
The base station acts as an intermediary to deliver control information from the relay device to the terminal device. The relay device sends control information (power control, timing advance) to the base station, which then transmits it to the terminal device via downlink, enabling indirect feedback without requiring direct relay-to-terminal downlink capability
Solution Approach 2:
The control information is nested within existing uplink message structures. The relay device embeds control information in uplink messages it relays to the base station, and the base station embeds this information in downlink messages to terminal devices, utilizing existing message containers rather than creating separate feedback channels
2Device complexity
If relay devices forward messages without adding control information, then device complexity is reduced, but transmission efficiency deteriorates due to lack of power control and timing synchronization
Solution Approach 1:
The control information generation function is extracted from the relay device and placed at the base station. The relay device only needs to forward messages and embed basic control information, while the base station performs the complex task of generating and delivering power control and timing advance commands, reducing relay complexity while maintaining transmission efficiency
Solution Approach 2:
The base station prepares control information in advance based on uplink message contents and device characteristics. By pre-calculating power control and timing advance parameters before downlink transmission, the system ensures efficient transmission without requiring complex real-time processing at the relay device
Data Source
AI summary
A wireless communications system is described which comprises a base station, a relay device, and a terminal device. The terminal device is operable to transmit a message to the base station via the relay device. The relay device is operable to add a relay header to the message received from the terminal device, the relay header comprising control information for controlling the transmission of subsequent messages from the terminal device to the relay device. The relay device is also operable to relay the message having the relay header added to the base station. By adding such control information to messages being relayed from the terminal device to the base station on the uplink, subsequent downlink communications from the base station to the terminal device can include the control information generated at the relay device (or transmission parameters derived from the control information).