Variable Group Boundary Downlink Subframes for FDD Synchronization
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Solution Overview
Problem
In wireless networks using Frequency Division Duplexing (FDD), Half Duplex-FDD mobile stations face challenges in maintaining synchronization due to variable group boundaries in downlink subframes, leading to inefficiencies and potential loss of synchronization, especially when transitioning from low power modes or during handovers.
Innovation Solution
The method involves transmitting downlink subframes with variable group boundaries, where group boundary information is included in both group 1 and group 2 portions, allowing mobile stations to determine the correct group boundary even when out of sync, and providing this information in both portions to facilitate quick recovery and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable group boundaries are used in downlink subframes to improve resource allocation flexibility, then network resource utilization is improved, but synchronization maintenance becomes more difficult for mobile stations
Solution Approach 1:
The patent applies preliminary action by including group boundary information in advance in both group 1 and group 2 portions of the downlink subframe. This allows mobile stations to have the synchronization information readily available before it is needed, enabling them to quickly determine their group boundary location even when transitioning from low power modes or experiencing synchronization loss, thus resolving the contradiction between flexible resource allocation and reliable synchronization maintenance
2Device complexity
If group boundary information is included only in one group portion, then downlink subframe structure is simplified, but mobile stations cannot determine correct group boundary when out of sync
Solution Approach 1:
The patent applies local quality by placing group boundary information in both group 1 and group 2 portions with different local functions. Each group portion has the capability to provide synchronization information independently, so that regardless of which group a mobile station belongs to or which group information it can successfully decode, it can always obtain the group boundary information needed for synchronization recovery
3Reliability
If mobile stations must perform network re-entry to recover synchronization, then synchronization can be restored, but network efficiency decreases due to time consumption
Solution Approach 1:
The patent applies self-service by enabling mobile stations to autonomously recover synchronization using the group boundary information contained in the downlink subframe itself. Mobile stations can determine their group boundary location and restore synchronization without needing to initiate a full network re-entry procedure, thus maintaining reliability while significantly improving network efficiency by eliminating time-consuming re-entry processes
Data Source
AI summary
Various example embodiments are disclosed herein. According to an example embodiment, an apparatus may include a wireless interface, and a controller, the apparatus being configured to: transmit a downlink subframe of a frequency division duplex (FDD) frame to one or more mobile stations in a wireless network, each wireless station being assigned to one of a plurality of groups, such as, for example, one of group 1 or group 2, the downlink subframe including at least: a group 1 portion and a group 2 portion, wherein a group boundary between the group 1 portion and the group 2 portion of the downlink subframe is variable, at least one of the group 1 portion and the group 2 portion including a group boundary information identifying a location of the group boundary or a location of the group 2 portion in the downlink subframe.