Multi-User Clustering and Scheduling in WLAN Systems
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Solution Overview
Problem
Current wireless local area network (WLAN) systems with very high throughput (VHT) face limitations in supporting large numbers of clusters for multiple user transmission schemes, combining orthogonal frequency-division multiple access (OFDMA) clusters and orthogonal frequency-division multiplexing (OFDM) MU-MIMO groups, and flexible clustering and scheduling mechanisms.
Innovation Solution
The implementation of new multi-user clustering and scheduling mechanisms that support a large number of clusters for multiple MU transmission schemes, including a combination of OFDMA clusters and OFDM MU-MIMO groups, with flexible clustering and scheduling enabled per transmission. This involves defining new MU control frames for polling and scheduling, and using null data packets (NDPs) to carry MU control messages, reducing overhead and improving MAC efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If new multi-user clustering and scheduling mechanisms are implemented to support a large number of clusters for multiple MU transmission schemes, then the system spectral efficiency and number of simultaneous users are improved, but the device complexity and control overhead increase
Solution Approach 1:
The patent segments the multi-user transmission system into distinct clusters, where each cluster contains a group of users that can be scheduled independently. This segmentation allows the system to manage a large number of users through multiple smaller clusters rather than managing all users as a single group, thereby improving spectral efficiency while keeping the complexity of each cluster manageable.
Solution Approach 2:
The patent implements dynamic clustering and scheduling mechanisms that allow clusters to be formed, modified, and dissolved based on current system conditions and user requirements. This dynamic approach enables the system to adapt to changing traffic patterns and user distributions, optimizing spectral efficiency without requiring a fixed complex structure for all possible user combinations.
2Adaptability or versatility
If new MU control frames are defined for polling and scheduling, then the flexibility of clustering and scheduling per transmission is improved, but the control overhead and MAC efficiency deteriorate
Solution Approach 1:
The patent designs MU control frames with multi-functional capabilities that can serve multiple purposes: polling multiple users, scheduling different cluster configurations, and carrying various types of control information. This universality allows a single control frame structure to handle diverse scheduling scenarios, reducing the need for multiple specialized control frames and thereby reducing overall control overhead while maintaining flexibility.
3Quantity of substance
If null data packets (NDPs) are used to carry MU control messages, then the control overhead is reduced and MAC efficiency is improved, but the measurement precision and reliability of control information may deteriorate
Solution Approach 1:
The patent extracts the essential control information from traditional MAC frames and places it into compact NDP structures. By taking out only the necessary control elements and removing redundant MAC layer overhead, the system achieves reduced control overhead and improved MAC efficiency while maintaining the critical control information needed for multi-user scheduling and clustering operations.
Data Source
AI summary
Methods, devices and systems are provided for performing for multi-user (MU) transmission. A wireless transmit/receive unit (WTRU) may be configured to receive a frame, decode the received frame and determine whether the received frame is a null data packet (NDP) multi-user (MU) media access control (MAC) physical layer convergence protocol (PLCP) protocol data unit (PPDU) (NDP MU MAC PPDU) based on meeting an NDP condition. The NDP MU MAC PPDU may correspond to an MU transmission and may include a PLCP header which includes an NDP signal (SIG) field having MU control information. Based on the received frame meeting the NDP condition, the WTRU may be further configured to process the NDP SIG field, generate a response based on the NDP SIG field and the MU control information, and transmit the response.