Multi-Subframe Scheduling in Enhanced LAA Systems
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Solution Overview
Problem
Current LTE-U systems face challenges in efficient multi-user equipment scheduling due to spectral emission issues, especially in the 6 GHz spectrum, leading to interference and inefficient radio resource utilization, particularly with beamforming technology.
Innovation Solution
The proposed method involves multi-subframe scheduling and interference mapping to allocate dedicated spectral resources, using listen before talk (LBT) procedures and interference detection to ensure fair coexistence of radio access technologies, and beamforming-based systems account for spatial proximity to minimize spectral emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-user equipment scheduling is performed in LTE-U systems, then radio resource utilization is improved, but spectral emission causes interference and reduces system reliability
Solution Approach 1:
The patent applies local quality by implementing beamforming technology that directs transmission signals along specific spatial paths between the eNodeB and user equipment. This creates localized communication channels with concentrated energy, improving radio resource utilization while minimizing spectral emission in other directions. The beamforming weights and spatial filtering ensure that interference is confined to specific angular regions rather than radiating omnidirectionally
Solution Approach 2:
The patent introduces listen-before-talk (LBT) procedures as an intermediary mechanism that mediates access to the unlicensed spectrum. Before transmitting, user equipment and the eNodeB perform channel sensing to detect ongoing transmissions from other systems (such as Wi-Fi). This intermediary sensing step prevents collisions and reduces harmful spectral emission by ensuring transmissions only occur when the channel is clear, thereby improving both resource utilization and system reliability
2Productivity
If beamforming technology is used in 6 GHz spectrum, then transmission efficiency is improved, but spatial proximity issues cause spectral emission and interference
Solution Approach 1:
The patent implements dynamic beam management where the beamforming configuration is continuously adapted based on channel conditions, user equipment mobility, and interference environment. The system dynamically adjusts beam directions, widths, and power levels to maintain efficient transmission while minimizing spectral emission. This dynamic adaptation allows the system to respond to changing spatial proximity conditions and prevent harmful interference
Solution Approach 2:
The patent addresses spatial proximity issues by introducing angular and spatial dimensions to the resource allocation problem. Instead of treating all user equipment equally in the time-frequency domain, the system allocates specific spatial beams and angular sectors to different users. This dimensional separation in the spatial domain allows simultaneous transmissions to nearby user equipment without causing harmful spectral emission, as each transmission is confined to its designated spatial path
3Adaptability or versatility
If listen before talk procedures are implemented, then coexistence with other radio access technologies is improved, but channel access time increases
Solution Approach 1:
The patent implements a tiered LBT approach where different sensing durations and probability thresholds are applied based on the priority, service type, and channel conditions. For high-priority traffic or favorable conditions, the system uses partial sensing with shorter listen periods, reducing channel access time while maintaining adequate coexistence. For lower-priority traffic or congested channels, more extensive sensing is performed. This partial action approach balances coexistence capability with time efficiency
Data Source
AI summary
A method which allows an evolved node B (eNB) to perform multi-subframe scheduling in enhanced license assisted access (eLAA) is provided. The eNB determining the subframes in a maximum channel occupancy time (MCOT) within which uplink transmission is performed. The eNB schedules resources for uplink transmission by user equipments (UEs) within the determined subframes. The UEs receive index values associated with a first subframe and a last subframe, in the determined subframes from the eNB. The first subframe and last subframe may be within a single, or multiple MCOTs. The UEs perform uplink transmission between the first subframe and the last subframe. The method allows forming a group with the plurality of UEs. A group identity, broadcast by the eNB, is received by the UEs. The method allows scheduling beams for performing uplink transmission by the UEs in 5th generation (5G) systems and scheduling multiple UEs while accounting spectral emissions.