Radio Terminal Access Control for Space Multiplexing Interference
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Solution Overview
Problem
Wireless LAN systems using the IEEE802.11 standard with SDMA schemes face interference issues due to simultaneous transmission and reception of data packets, leading to collisions, as existing methods do not effectively manage packet transmission and reception timing among multiple radio terminals.
Innovation Solution
A radio system where radio terminals request access rights and transmit data packets under a space multiplexing scheme, with a base station assigning access rights to multiple terminals to transmit simultaneously, and terminals preventing signal transmission during designated periods to avoid collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the radio base station transmits data packets spatially multiplexed to multiple radio terminals simultaneously, then system capacity and throughput are improved, but interference and collisions occur between transmitted and received packets
Solution Approach 1:
The patent applies preliminary action by having the radio base station transmit a notification signal before transmitting spatially multiplexed data packets. This notification signal contains information about the timing and resources allocated for subsequent packet transmissions. By providing this advance notice, terminals can prepare their response packets and prevent collisions before they occur, allowing the base station to maintain high system capacity while ensuring reliable packet delivery.
2Reliability
If the radio base station waits for response packets from all terminals before transmitting the next packet, then collision is avoided, but transmission efficiency and throughput decrease
Solution Approach 1:
The notification signal provides advance information about future transmission timing, allowing the base station to schedule subsequent packets without waiting for all response packets to be received. This enables overlapping transmission and reception operations in different spatial streams, maintaining collision avoidance while significantly improving transmission efficiency and overall system throughput.
3Ease of operation
If multiple radio terminals transmit response packets at different timings, then individual terminal responses are maintained, but interference occurs between response packets
Solution Approach 1:
The patent merges the timing control of response packets by having the base station provide unified timing information in the notification signal to all terminals. This coordinates the transmission timing of response packets from multiple terminals, allowing them to transmit simultaneously without interference. The merging of timing control maintains terminal response autonomy while eliminating response packet interference.
Data Source
AI summary
One of a plurality of radio terminals that transmit radio signals to a radio base station under a space multiplexing scheme, including a receiving unit that receives an access right request signal with respect to the radio base station from an other radio terminal, a prevention unit that prevents transmission of radio signals when receiving radio signals directed to an other radio terminal, a cancellation unit that cancels the prevention of transmission when receiving an access right assignment signal during the prevention of transmission and a transmitting unit that transmits a data signal to the radio base station according to the assignment signal, wherein radio signals are transmitted to the radio base station simultaneously with the other radio terminals and under the space multiplexing scheme.