Wireless Repeater Transmission Period Scheduling for Hidden Node Resolution
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Solution Overview
Problem
In wireless communication configurations where a repeater is interposed between a parent device AP and a child device STA, issues such as the 'hidden node' problem lead to inefficient transmission time usage and packet loss due to signal interference and imbalanced data transmission, resulting in deteriorated communication efficiency.
Innovation Solution
A method that sets distinct transmission periods for the first and second links based on the amount of data to be communicated, ensuring these periods do not overlap, and controls wireless devices to limit transmissions within these designated periods to prevent collisions and packet loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a repeater is interposed between parent device AP and child device STA to extend wireless communication range, then communication coverage is improved, but hidden node problem occurs causing transmission efficiency to deteriorate
Solution Approach 1:
The repeater performs preliminary actions by transmitting reservation signals before actual data transmission and by accumulating data packets in its buffer when reception capacity exceeds transmission capacity. This preliminary buffering and reservation signaling prevents hidden node collisions and packet loss by ensuring the repeater is ready to forward packets without overflow or interference.
Solution Approach 2:
The repeater acts as an intermediary device that mediates communication between the parent AP and child STA. It transmits reservation signals to coordinate transmission timing and uses its buffer as an intermediary storage to balance data flow imbalances, thereby resolving the hidden node problem and improving overall transmission efficiency.
2Productivity
If data transmission is allowed continuously on both links simultaneously, then data throughput is improved, but frame collision occurs causing transmission reliability to deteriorate
Solution Approach 1:
The system implements periodic action by dividing transmission into distinct phases: a first period for parent-to-repeater transmission and a second period for repeater-to-child transmission. This periodic time-division approach allows continuous data throughput while preventing frame collisions by ensuring only one link transmits at any given time.
Solution Approach 2:
The transmission timeline is segmented into separate first and second periods for different communication links. This segmentation prevents overlapping transmissions that would cause frame collisions, while the repeater's buffer ensures continuous data flow by decoupling the segmented transmission phases from the continuous data generation rate.
3Adaptability or versatility
If transmission time is restricted per device to prevent imbalance, then communication fairness is improved, but packet loss occurs when repeater buffer reaches upper limit
Solution Approach 1:
The repeater performs preliminary buffering of incoming data packets during the first transmission period before the second period begins. By accumulating packets in its buffer during periods when reception capacity exceeds transmission capacity, the repeater prepares data for future transmission, preventing packet loss even when transmission time is restricted for fairness.
Solution Approach 2:
The system dynamically adapts to transmission time restrictions by using the repeater's buffer to absorb imbalances between reception and transmission rates. When transmission time is limited, the buffer dynamically stores excess incoming packets, and when transmission capacity becomes available, it releases stored packets, thereby maintaining communication fairness without packet loss.
4Quantity of substance
If repeater accumulates large amount of data in buffer, then data transmission capacity is improved, but packet loss occurs when buffer reaches upper limit
Solution Approach 1:
The periodic alternation between first and second transmission periods allows the repeater to accumulate data during the first period when reception capacity is high, then transmit during the second period. This periodic rhythm ensures the buffer utilizes its full capacity without overflow, as transmission is guaranteed to follow accumulation phases.
Solution Approach 2:
The repeater performs preliminary data accumulation in its buffer during the first transmission period before the second period begins. This preliminary buffering ensures that data is ready for transmission without exceeding buffer limits, as the periodic structure guarantees transmission opportunities follow accumulation phases.
Data Source
AI summary
A network includes: a first link between a first STA as a repeater and a first AP as a parent device; and a second link between a second STA as a child device and the first STA. A first transmission time is set during which transmission is permitted to the first link based on a first amount of transmission. A second transmission time is set during which transmission is permitted to the second link based on a second amount of transmission. An entire transmission cycle is determined based on the first transmission time and the second transmission time. A first transmission period and a second transmission period do not overlap in the entire transmission cycle. Wireless communication performed on the first link is limited within the first transmission period. Wireless communication performed on the second link is limited within the second transmission period.