Broadcast Channel Timing Detection Using Segmented Mapping

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In LTE cellular communication systems, determining the 40 ms timing for BCH transport block transmission is challenging, especially when decoding is done using fewer than all available subframes, as it leads to ambiguity in identifying the correct timing and subframe usage, particularly during initial cell access or handover between unsynchronized cells.

Innovation Solution

The solution involves coding the BCH transport block into Nframes segments, applying unique mapping functions to each segment, and transmitting a different segment in each frame, allowing for correct decoding from any segment while using inverse mapping functions to determine the correct timing by testing for decodability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If BCH transport block is transmitted across multiple frames and decoded using fewer than all subframes, then power consumption is reduced and decoding efficiency is improved, but timing ambiguity increases and correct timing identification becomes difficult

Engineering Contradiction:

Improvepower consumptionVSAvoidtiming information

Core Design Contradiction:

Use of energy by moving objectVSLoss of information

Solution Approach 1:

The BCH transport block is segmented into multiple segments, with each segment transmitted in a different frame. The terminal can decode the BCH using fewer than all segments, reducing power consumption. Each segment contains sufficient information for independent decoding, enabling flexible reception strategies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different scrambling sequences are applied to different BCH segments transmitted in different frames. This scrambling differentiation allows the terminal to identify and correlate segments properly, resolving timing ambiguity even when using fewer than all segments for decoding. The scrambling acts as a unique identifier for each segment's temporal position.

Inventive Principle:

Principle #32Color changes

2Reliability

If BCH transport block is transmitted across multiple frames, then reliability is improved through diversity, but device complexity increases due to need to track and combine multiple segments

Engineering Contradiction:

Improvedecoding reliabilityVSAvoidsegment tracking complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The BCH transport block is divided into multiple segments transmitted across different frames, providing time diversity and improved reliability. Each segment is self-contained and can be independently decoded, simplifying the reception process compared to requiring all segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple segments contain redundant information from the same BCH transport block. The terminal can decode from any single segment without needing to track or combine multiple segments, eliminating complex tracking requirements while maintaining reliability through redundant transmission.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If primary synchronization signal is transmitted twice per frame, then handover from GSM to LTE is simplified, but 5 ms timing ambiguity is created

Engineering Contradiction:

Improvehandover capabilityVSAvoidframe timing precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The primary synchronization signal is transmitted periodically twice per frame, enabling flexible handover from GSM to LTE systems. This periodic transmission pattern provides multiple opportunities for terminal detection and synchronization.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Different scrambling sequences are applied to different occurrences of the primary synchronization signal within a frame. This scrambling differentiation allows terminals to distinguish between the two transmissions and resolve the 5 ms timing ambiguity while maintaining handover capability.

Inventive Principle:

Principle #32Color changes

Data Source

PatentEP2145443B1Broadcast channel timing detection

Publication Date: 2017.10.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A broadcast control channel (BCH) transport block is communicated in a cellular communications system having a physical layer in which information is communicated in one or more frames, wherein the BCH transport block represents BCH information. This involves coding (901 ) the BCH transport block (1001. 1101) to generateM bits of coded information. Nframes segments of coded bits are formed (903) from the M bits of coded information, wherein the BCH information can be derived from any one of the Nframes segments of coded bits. A unique one of Nframes mapping functions is applied (905) to each of the Nframes segments of coded bits to produce Nframes mapped segments of coded bits. A different one of the Nframes mapped segments of coded bits is transmitted (907) in each of Nframes frames. This enables multi-frame timing to be determined even when fewer than all BCH segments are received.