Guard Period Configuration for Cellular D2D Subframe Transitions
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Solution Overview
Problem
In mixed cellular and Device-to-Device (D2D) networks, User Equipment (UE) faces challenges in managing communication transitions between cellular and D2D subframes, leading to potential data loss due to overlap and interference, as existing solutions do not adequately address the need for proper operation at these transitions.
Innovation Solution
The implementation of a method where the UE determines and configures a Guard Period (GP) at the beginning and/or end of D2D subframes to ensure proper operation during transitions, using timing advances specific to cellular and D2D communications, thereby preventing data loss by aligning transmission and reception timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If D2D communications share radio resources with cellular communications to achieve capacity gain, then resource utilization efficiency is improved, but interference between D2D and cellular transmissions increases
Solution Approach 1:
The patent segments the radio frame into distinct subframe types (D2D subframes and cellular subframes) with clear boundaries. D2D subframes are specifically designated for D2D communications while cellular subframes are for cellular communications, reducing resource conflicts and interference between the two communication types.
Solution Approach 2:
The patent introduces a Guard Period (GP) as an intermediary time interval between D2D and cellular transmissions. This GP acts as a buffer that prevents direct interference between D2D and cellular signals by ensuring proper timing alignment and preventing transmission overlap at subframe boundaries.
2Reliability
If Guard Period is configured to protect against transmission overlap at cellular DL/UL transitions, then interference protection is improved, but the GP does not protect D2D subframe transitions causing data loss
Solution Approach 1:
The patent extends the Guard Period concept to segment and protect D2D subframe transitions specifically. By configuring GP at both the beginning and end of D2D subframes, the patent creates dedicated protection intervals for D2D communications, separate from the cellular DL/UL transition protection.
Solution Approach 2:
The patent configures Guard Period in advance at strategic positions within the D2D subframe structure (at the beginning and/or end of D2D subframes). This preliminary configuration ensures that protection intervals are already in place before D2D transmissions occur, preventing data loss at transitions without requiring reactive measures.
3Measurement precision
If timing advances are used to align transmissions at eNB, then cellular transmission synchronization is improved, but D2D transmissions experience overlap and interference
Solution Approach 1:
The patent applies different timing advance principles to different communication types. Cellular UEs use TA relative to eNB for precise alignment at the eNB, while D2D UEs use TA relative to their own transmissions for precise alignment at the D2D receiver. This local optimization of timing alignment prevents interference in both communication types.
Solution Approach 2:
The patent segments the timing advance mechanism into separate domains: cellular TA for eNB-aligned communications and D2D TA for D2D-aligned communications. By configuring separate TA values and reference points for each communication type, the patent prevents timing conflicts and interference between cellular and D2D transmissions.
Data Source
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AI summary
The present disclosure discloses a communication method performed by a User Equipment (UE) (301) in a mixed cellular and Device-to-Device (D2D) network (300) and the UE. The method comprises the step of communicating in the mixed network according to a radio frame structure, wherein the radio frame structure comprises at least one D2D subframe having a Guard Period (GP) at an end or at a beginning of the D2D subframe.