Mobile Station Base Sequence Generation for Interference Reduction

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Solution Overview

Problem

In LTE systems, the existing methods cannot assign different base sequences for DMRS to mobile station apparatuses communicating with the same cell, leading to interference issues due to shared frequency bands.

Innovation Solution

A mobile station apparatus generates a demodulation reference signal sequence based on a sequence group number and transmits it with the physical uplink shared channel, using parameter information received from the base station, even during contention-based random access procedures, to efficiently determine the sequence group number without relying on cell-specific parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If different base sequences are assigned to mobile station apparatuses in different cells, then interference between cells is reduced, but it becomes impossible to assign different base sequences to mobile station apparatuses communicating with the same cell

Engineering Contradiction:

Improveinterference between cellsVSAvoidability to assign different base sequences

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The base sequence assignment is segmented into two independent dimensions: cell-specific parameters (physical cell ID) and apparatus-specific parameters (apparatus ID, C-RNTI). This segmentation allows different base sequences to be assigned within the same cell by utilizing the apparatus-specific dimension, while still maintaining cell-specific differentiation through the cell-specific dimension.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional dimension for base sequence differentiation by incorporating apparatus-specific parameters (such as apparatus ID or C-RNTI) into the base sequence determination formula. This transforms the single-dimensional cell-specific assignment into a multi-dimensional assignment system, enabling unique base sequence identification for each mobile station apparatus within a cell.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If cell-specific parameters are used for base sequence determination, then base sequences are uniquely determined per cell, but multiple mobile stations in the same cell must share the same base sequence causing interference

Engineering Contradiction:

Improveunique base sequence determinationVSAvoidinterference from shared base sequences

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The base sequence determination is segmented into cell-specific components and apparatus-specific components. The cell-specific parameters ensure reliable and consistent base sequence determination for channel estimation, while the apparatus-specific parameters differentiate between multiple mobile stations, eliminating interference caused by shared base sequences.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the base sequence determination process serve different functions: cell-specific parameters provide the fundamental base sequence structure for reliable channel estimation, while apparatus-specific parameters provide local differentiation to eliminate interference between mobile stations in the same cell.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the same base sequence is used by multiple mobile stations in the same cell, then implementation is simplified, but interference occurs in frequency bands where PUSCH transmissions overlap

Engineering Contradiction:

Improveimplementation simplicityVSAvoidinterference in overlapping frequency bands

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The base sequence assignment is segmented into cell-level configuration (maintaining implementation simplicity) and apparatus-level differentiation (reducing interference). The mobile station apparatus determines its base sequence by combining cell-specific parameters received from the base station with its own apparatus-specific parameters, achieving both simplicity and interference reduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each mobile station apparatus autonomously determines its base sequence by combining cell-specific parameters (received from base station) with its own apparatus-specific parameters (such as C-RNTI or apparatus ID). This self-service mechanism eliminates interference without requiring complex centralized coordination, maintaining implementation simplicity.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11438929B2Mobile station apparatus, base station apparatus, wireless communication method, and integrated circuit

Publication Date: 2022.09.06 SHARP KK

AI summary

To make a mobile station apparatus efficiently generate a base sequence. In a mobile station apparatus that generates a sequence for a demodulation reference signal on the basis of at least a sequence group number and transmits to a base station apparatus the demodulation reference signal together with a physical uplink shared channel used for transmission of a transport block, the mobile station apparatus receives information indicating a value of a parameter relating to the sequence from the base station apparatus, and determines the sequence group number without using the value of the parameter in a case where the mobile station apparatus performs transmission of the transport block on the physical uplink shared channel as part of a contention based random access procedure.