MBSFN Subframe Segmentation for Short TTI Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems, particularly 3GPP LTE, face challenges in reducing packet data latency, which affects system responsiveness and throughput, and existing techniques do not fully address the inefficiencies in handling multicast-broadcast single-frequency network (MBSFN) subframes for short transmission time intervals (TTI), leading to suboptimal latency reduction.
Innovation Solution
A method and apparatus for handling MBSFN subframes using a short TTI in a backward compatible manner, where a network performs downlink transmissions via both MBSFN and short TTI subframes, with the short TTI being less than 1 ms, and employs frequency division multiplexing (FDM) between short and legacy TTI subframes to minimize unavailable subframes, allowing for efficient latency reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If short TTI is used to reduce latency, then packet data latency is reduced and system responsiveness is improved, but MBSFN subframes become unavailable for short TTI transmission causing resource utilization to deteriorate
Solution Approach 1:
The patent segments the subframe into two parts: a first portion used for MBSFN transmission and a second portion used for short TTI transmission. This segmentation allows both MBSFN services and short TTI data transmissions to coexist within the same subframe, resolving the conflict between maintaining MBSFN availability and enabling short TTI latency reduction.
Solution Approach 2:
The patent introduces a frequency domain dimension by allocating different frequency resources to MBSFN and short TTI transmissions within the same time subframe. This dimensional separation allows both transmission types to proceed simultaneously without mutual interference, turning the previously unavailable MBSFN subframes into useful resources for short TTI transmission.
2Loss of time
If MBSFN subframes are made unavailable for short TTI, then short TTI latency reduction is compromised, but backward compatibility with legacy systems is maintained
Solution Approach 1:
The patent makes the subframe structure universal by enabling it to serve multiple functions: MBSFN transmission in the first portion and short TTI data transmission in the second portion. This multi-functionality allows the system to maintain backward compatibility with legacy MBSFN operations while simultaneously supporting advanced short TTI latency reduction features.
Solution Approach 2:
The patent introduces dynamic flexibility by allowing the eNodeB to configure different transmission modes (MBSFN-only, short TTI-only, or combined) based on real-time traffic conditions and network requirements. This dynamic adaptation enables the system to optimize performance for different scenarios while maintaining compatibility across diverse network configurations.
3Productivity
If frequency division multiplexing is used between short and legacy TTI subframes, then resource efficiency is improved, but system complexity increases
Solution Approach 1:
The patent applies local quality differentiation by assigning specific frequency resources to specific transmission types: certain frequency bands are dedicated to MBSFN transmission while others are allocated for short TTI transmission. This localized resource allocation optimizes resource efficiency for each transmission type while keeping the overall system management straightforward through clear frequency-domain separation.
Data Source
AI summary
A method and apparatus for performing a downlink (DL) transmission using a short transmission time interval (TTI) is provided. A network performs a first DL transmission via a first set of subframes which are multicast-broadcast single-frequency network (MBSFN) subframes, and performs a second DL transmission via a second set of subframes using the short TTI. A length of the short TTI is less than 1 ms.