MathWorks - Mobile View
  • Sign In to Your MathWorks AccountSign In to Your MathWorks Account
  • Access your MathWorks Account
    • My Account
    • My Community Profile
    • Link License
    • Sign Out
  • Products
  • Solutions
  • Academia
  • Support
  • Community
  • Events
  • Get MATLAB
MathWorks
  • Products
  • Solutions
  • Academia
  • Support
  • Community
  • Events
  • Get MATLAB
  • Sign In to Your MathWorks AccountSign In to Your MathWorks Account
  • Access your MathWorks Account
    • My Account
    • My Community Profile
    • Link License
    • Sign Out

Videos and Webinars

  • MathWorks
  • Videos
  • Videos Home
  • Search
  • Videos Home
  • Search
  • Contact sales
  • Trial software
  Register to watch video
  • Description
  • Full Transcript
  • Related Resources

5G Explained: Uplink Control Information in 5G NR

From the series: Understanding the 5G NR Standard

Marc Barberis, MathWorks

Learn about uplink control information, or UCI, in 5G New Radio.

This video walks through the different types of messages, including HARQ, CQI, and scheduling requests. It discusses how they are encoded, modulated, and then mapped to the 5G New Radio slot via the PUCCH or physical uplink control channel. Finally, you’ll learn how control information is used in 5G NR procedures.

This is a new episode of our series, "5G Explained." In this video, we discuss uplink control information or UCI in 5G New Radio. We will look at its content, how it is encoded and modulated, then mapped to the 5G New Radio slot via the PUCCH or physical uplink control channel. We will look at examples of usage and how it can be used for scheduling requests.

Uplink control information or UCI is very different from downlink control information or DCI. You may recall from another episode of this "5G Explained" series that DCI carries scheduling information for downlink and uplink, among other pieces of information. UCI content is more limited as the base station is already aware of all scheduled transmissions. It includes acknowledgments for previously transmitted blocks, channel quality indicators, or CQI, which lets the base station make decisions about beamforming and scheduling, as well as scheduling requests. Those pieces of information can be combined and transmitted simultaneously. The UCI is carried by the PUCCH or physical uplink control channel. It can also be carried on the PUSCH if a PUSCH transmission is scheduled.

Depending on the content of the UCI, one or more of several formats can be used. There are two basic cases for transmissions: payloads smaller than two bits and payloads larger than two bits. Payloads smaller that two bits use format 0 or format 1. Such payloads represent one or two ACK/NAK or scheduling requests. Format 1 is a longer alternative to format 0, which is useful for power limited or cell edge scenarios. Payloads greater than two bits use format 2 or the longer alternatives, 3 or 4. These formats support longer payloads such as CQI, multiple HARQs, or a combination of different payloads. Note that UCI payloads can vastly exceed 100 bits when detailed CQI reports are included.

You will often hear that control uses polar coding, but this is only true, strictly speaking, for payloads greater than 11 bits. For shorter payloads, other schemes are used including repetition, simplex code, and Reed Muller code. This slide shows an overview of the PUCCH processing chain for different PUCCH formats. Of course, the chain is quite different for formats that support one or two bits, which is the first two, than for formats that support many bits. Those latter ones include coding and scrambling, whereas coding and randomization are taken care of by means of predefined sequences for the first two chains. The highest level modulation for any PUCCH is QPSK.

Here you can see code from MathWorks 5G Toolbox that implements the PUCCH chain for format 4, the most complicated chain from the previous slide. You can recognize steps such as scrambling, modulation, spreading, and transform precoding. The code also provides all necessary references to 3GPP standard documents. The first content type for UCI is scheduling requests.

Scheduling requests are the means for UE to request access to uplink resources not yet scheduled for transmission. The scheduling requests can be carried in one of two ways, through PUCCH or through RACH. The network may set up semi-statically allocated resources for the UE to send PUCCH, and the UE can use those resources to request data capacity on the uplink. If such resources have not been set up, then the UE must go through the contention-based and slower RACH process to request resources.

As explained in the episode of this "5G Explained" series about downlink control transmission, a downlink control information carrying and uplink grant comes in response to a scheduling request from the UE. When the receives the scheduling requests, it makes all the decisions about when and how the UE should transmit the data that is ready for transmission. Those parameters include--besides the time and frequency, location, and modulation and coding scheme--other information such as precoding, which comes in the form of an index that points to a table of possible precoding matrices. After decoding the control information for the uplink grant, the UE transmits uplink data according to those parameters.

The second type of UCI content is CQI or channel quality indicators. Such information is transmitted in response to a request from the [INAUDIBLE] These requests can be a onetime request, a semi-periodic, or a periodic request, as shown in more detail in another episode of this "5G Explained" series about channel sounding.

The third type of UCI content is ACK/NACK for HARQ. Each transport block transmitted on the downlink has to be acknowledged by the UE. The positive or negative acknowledgment determines whether a block has to be retransmitted at the physical layer or, if the maximum number of transmission has been already reached, skipped for higher layers to decide how to handle the failure. This concludes this episode of the "5G Explained" series on uplink control transmission.

Related Products

  • 5G Toolbox

Learn More

Get a free 5G Toolbox trial
Related Information
Download eBook: 5G New Radio Design with MATLAB

Feedback

Featured Product

5G Toolbox

  • Request Trial
  • Get Pricing

Up Next:

Learn about demodulation reference signals (DMRS) in 5G New Radio, including their use in channel estimation and the different configurations for signal and multi-user MIMO.
15:59
5G Explained: Demodulation Reference Signals in 5G NR
View full series (12 Videos)

Related Videos:

10:40
Acquiring System Information from an LTE Signal
3:52
Control System Design with the Control System Designer App
2:22
PID Control Design with Control System Toolbox
16:36
Renault's Model-Based Design Powertrain Control Development...
4:56
Automatic Tuning of a Helicopter Flight Control System

View more related videos

MathWorks - Domain Selector

Select a Web Site

Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .

Select web site

You can also select a web site from the following list:

How to Get Best Site Performance

Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.

Americas

  • América Latina (Español)
  • Canada (English)
  • United States (English)

Europe

  • Belgium (English)
  • Denmark (English)
  • Deutschland (Deutsch)
  • España (Español)
  • Finland (English)
  • France (Français)
  • Ireland (English)
  • Italia (Italiano)
  • Luxembourg (English)
  • Netherlands (English)
  • Norway (English)
  • Österreich (Deutsch)
  • Portugal (English)
  • Sweden (English)
  • Switzerland
    • Deutsch
    • English
    • Français
  • United Kingdom (English)

Asia Pacific

  • Australia (English)
  • India (English)
  • New Zealand (English)
  • 中国
    • 简体中文Chinese
    • English
  • 日本Japanese (日本語)
  • 한국Korean (한국어)

Contact your local office

  • Contact sales
  • Trial software

Explore Products

  • MATLAB
  • Simulink
  • Student Software
  • Hardware Support
  • File Exchange

Try or Buy

  • Downloads
  • Trial Software
  • Contact Sales
  • Pricing and Licensing
  • How to Buy

Learn to Use

  • Documentation
  • Tutorials
  • Examples
  • Videos and Webinars
  • Training

Get Support

  • Installation Help
  • Answers
  • Consulting
  • License Center
  • Contact Support

About MathWorks

  • Careers
  • Newsroom
  • Social Mission
  • Contact Sales
  • About MathWorks

MathWorks

Accelerating the pace of engineering and science

MathWorks is the leading developer of mathematical computing software for engineers and scientists.

Discover…

  • Select a Web Site United States
  • Patents
  • Trademarks
  • Privacy Policy
  • Preventing Piracy
  • Application Status

© 1994-2021 The MathWorks, Inc.

  • Facebook
  • Twitter
  • Instagram
  • YouTube
  • LinkedIn
  • RSS

Join the conversation