Interference Rejection Combining Feature Description 84/221 04-LZA 701 6014/1 Uen C2 Copyright © Ericsson AB 2016. All rights reserved. No part of this document may be reproduced in any form without the written permission of the copyright owner. Disclaimer The contents of this document are subject to revision without notice due to continued progress in methodology, design and manufacturing. Ericsson shall have no liability for any error or damage of any kind resulting from the use of this document. Trademark List All trademarks mentioned herein are the property of their respective owners. These are shown in the document Trademark Information. 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 Contents Contents 1 Introduction 1 1.1 Basic Characteristics 1 1.2 Interference Rejection Combining Summary 1 1.3 Additional Information 2 2 Feature Operation 3 2.1 Network Requirements 3 2.2 High Level Description 3 2.3 Interference Rejection Combining Process Steps 3 2.4 Eight-way Receiver IRC, TDD only 4 3 Parameters 5 3.1 Introduced Parameters 5 3.2 Affected Parameters 5 4 Network Impact 6 4.1 Capacity 6 4.2 Coverage 6 5 Associated Features and 7 5.1 Prerequisite Features 7 5.2 Affected Features 7 5.3 Related Features 7 5.4 Affected System Functions 7 6 Performance 8 6.1 KPIs 8 6.2 Counters 8 6.3 Events 8 7 O&M Information 9 7.1 Feature Activation and Deactivation 9 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 Interference Rejection Combining 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 Introduction 1 Introduction This document describes the Interference Rejection Combining feature and its main benefits and impacts in the LTE RAN. This document describes the feature . 1.1 Basic Characteristics This section describes the basic characteristics of the feature. Feature Identity DU Radio Node, see Feature Overview. Baseband Radio Node, see Licensed Feature Overview. Replaces: N/A Dependencies This feature has no prerequisite features. This feature affects no other features. 1.2 Interference Rejection Combining Summary This section describes the benefits of this feature. Interference Rejection Combining (IRC) is a method for antenna combining and is superior to Maximum Ratio Combining (MRC) when suppressing on received signals. IRC uses correlations in the spatial domain (between antennas) and in the frequency domain to suppress interfering signals from other cells or in-band external interferers. The Interference Rejection Combining feature improves the Block Error Rate (BLER) on the Physical Uplink Shared Channel (PUSCH) and Physical Uplink Control Channel (PUCCH) compared to MRC and improves uplink throughput in uplink interference limited systems. The use of IRC on uplink channels does not require any additional User Equipment (UE) support. IRC also improves false detection and missed detection performance on the Physical Random Access Channel (PRACH) in an inter-cell interference scenario. IRC is always available on the PRACH. 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 1 Interference Rejection Combining 1.3 Additional Information More information about this feature and related topics can be found in the following documentation: 2 • 3GPP TS 36.211 • 3GPP TS 36.212 • 3GPP TS 36.213 • Applications of Antenna Arrays to Mobile Communications, Part I: Performance Improvement, Feasibility, and System Considerations • Application of Antenna Arrays to Mobile Communications, Part II: BeamForming and Direction-of-Arrival Considerations 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 Feature Operation 2 Feature Operation This section describes the Interference Rejection Combining feature in more detail, including network configuration requirements and operation flows. 2.1 Network Requirements This is a licensed feature. This means that for the feature to be operational, a valid license key must be installed and the feature must be explicitly activated by setting a MOM attribute. See Section 7.1 on page 9 for more details. Prior to feature activation, at least two receive antennas must be installed for the cells on the RBS. If it is a TDD cell, up to eight receive antennas may be installed. 2.2 High Level Description The Interference Rejection Combining feature is a form of antenna combining that is superior to MRC in interference limited systems. This licensed feature enables the operator to improve the suppression of intercell interference by using Interference Rejection Combining. When the feature is enabled, the RBS will decide to use the Interference Rejection Combining feature instead of MRC in interference limited situations. 2.3 Interference Rejection Combining Process Steps This section describes the main process steps for the feature flow. 2.3.1 Interference Suppression Figure 1 shows how the Interference Rejection Combining feature can be used in the antenna combiner rather than MRC to improve interference suppression. 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 3 Interference Rejection Combining Antenna combiner Equalizer Decoder L0000494A Figure 1 IRC As Antenna Combiner Rather than MRC The Interference Rejection Combining feature maximizes the Signal to Interference and Noise Ratio (SINR) of the combined signal by minimizing the noise and interference at the antenna combiner output while preserving the signal. It can be seen as weighting down the signal in the directions of the interferers, so that they do not corrupt the signal from the desired user. 2.4 Eight-way Receiver IRC, TDD only An eight-way receiver IRC solution has been developed for PUCCH, PUSCH and PRACH, large capacity and coverage improvements are expected when going from two-way receiver to eight-way receiver diversity. 4 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 Parameters 3 Parameters This section describes the parameters introduced by the Interference Rejection Combining feature and parameters affected by activating the feature. 3.1 Introduced Parameters This feature does not introduce any new parameters. 3.2 Affected Parameters The implementation of this feature affects no parameters. 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 5 Interference Rejection Combining 4 Network Impact This section describes how the Interference Rejection Combining feature impacts the network functions and capabilities. 4.1 Capacity This section provides information on the impact of the feature on network capacity. This feature will increase the uplink capacity of the system. 4.2 Coverage This section provides information on the impact of the feature on network coverage. This feature may increase the coverage active UE in uplink interference limited environments. 6 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 Associated Features and 5 Associated Features and This section describes how the Interference Rejection Combining feature affects other features and functions. 5.1 Prerequisite Features This feature has no prerequisite features. 5.2 Affected Features This feature affects no other feature. 5.3 Related Features This feature is not related to any other feature. 5.4 Affected System Functions This feature affects no system functions. 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 7 Interference Rejection Combining 6 Performance This section describes performance indicators, counters, and events associated with the Interference Rejection Combining feature. 6.1 KPIs This feature has no associated Key Performance Indicators (KPIs). 6.2 Counters This feature has no directly associated counters. 6.3 Events This feature has no associated events. 8 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 O&M Information 7 O&M Information This section provides Operation and Maintenance (O&M) information for the Interference Rejection Combining feature. 7.1 Feature Activation and Deactivation Activating the feature requires that the corresponding license is installed. When the license is installed, an MO instance Irc is automatically created. Table 1 Feature MO Instance Node type MO instance DU Radio Node MO instance is OptionalFeatureLicense =Irc Baseband Radio Node MO instance is FeatureState =Irc Feature activation and deactivation is described in Manage Licenses. 84/221 04-LZA 701 6014/1 Uen C2 | 2016-06-06 9
