Cyclic Shift Parameter for MIMO Orthogonality

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Solution Overview

Problem

Current wireless communication systems, particularly in LTE and LTE-A environments, face challenges in maintaining orthogonality between reference signals in MIMO systems, leading to inefficiencies in channel estimation and data transmission due to the need for separate signaling of cyclic shift and OCC parameters, which increases overhead and complicates resource allocation.

Innovation Solution

The method involves implicitly transmitting cyclic shift parameters that also indicate orthogonality information, allowing User Equipment (UE) to infer and set OCC and orthogonality allocation rules without additional signaling, thereby enabling efficient reference signal generation and transmission in both SU-MIMO and MU-MIMO environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate signaling of cyclic shift and OCC parameters is used, then orthogonality between reference signals is maintained, but overhead increases and resource allocation becomes complicated

Engineering Contradiction:

Improveorthogonality between reference signalsVSAvoidresource allocation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the cyclic shift parameter and OCC parameter into a single cyclic shift parameter that serves dual purposes. The base station determines a cyclic shift parameter for the first layer, and this same parameter is used to determine both the cyclic shift and the OCC for reference signals across multiple layers, eliminating the need for separate OCC signaling while maintaining orthogonality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cyclic shift parameter is given multi-functionality by using it to determine both cyclic shift values and OCC values. The patent establishes that the cyclic shift parameter for the first layer can be used to derive cyclic shift parameters for subsequent layers, and simultaneously determine OCC parameters, making a single parameter serve multiple functions in maintaining orthogonality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate signaling of cyclic shift and OCC parameters is used, then orthogonality between reference signals is maintained, but overhead increases

Engineering Contradiction:

Improveorthogonality between reference signalsVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges the separate OCC parameter signaling into the cyclic shift parameter determination process. By using the cyclic shift parameter of the first layer to determine both cyclic shifts and OCCs for multiple layers, the patent eliminates redundant OCC parameter signaling and reduces overall control information overhead.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the OCC determination function from the separate OCC parameter signaling and integrates it into the cyclic shift parameter processing. This extraction eliminates the need for additional OCC parameter transmission while preserving the orthogonality function that OCCs provide.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If cyclic shift parameters are implicitly transmitted, then overhead is reduced and resource allocation is simplified, but separate orthogonality signaling is eliminated

Engineering Contradiction:

Improveresource allocation complexityVSAvoidorthogonality between reference signals

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent combines the orthogonality maintenance function into the cyclic shift parameter determination. By using the first layer's cyclic shift parameter to derive both cyclic shifts and OCCs for other layers, the patent maintains orthogonality through implicit parameter transmission rather than explicit separate signaling.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cyclic shift parameter of the first layer serves itself to determine parameters for other layers. The patent enables the first layer's parameter to automatically provide the necessary information for maintaining orthogonality in subsequent layers without requiring additional dedicated signaling resources.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP3379738B1Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in MIMO environment

Publication Date: 2020.08.19 APPLE INC

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AI summary

A method, comprising: receiving a Cyclic Shift, CS, parameter from a Base Station, BS; and transmitting, to the BS, reference signals for 4 layers, the reference signals being generated based on the CS parameter and an Orthogonal Cover Code, OCC, wherein if the CS parameter comprises one of 000, 001, 010 and 111, OCCs of a first layer and a second layer are identical and OCCs of a third layer and a fourth layer are identical while the OCC of the third layer is different from the OCC of the first layer, and wherein if the CS parameter comprises one of 101, 011,100 and 110, an OCC is identically allocated to all of the 4 layers.