August’s Recap: LinkedIn Posts

September 1, 2019

• 15 kHz as 5G Baseline Numerology

• 5G RRC States

In 5G and the previous generations, the device can be in different states depending on the traffic activity. NR device can be in one of three RRC states, RRC_IDLE, RRC_ACTIVE, and RRC_INACTIVE. The first two RRC states, RRC_IDLE and RRC_CONNECTED, are similar to the counterparts in LTE, while RRC_INACTIVE is a new state introduced in NR and not present in the original LTE design.

• Types of Spectrum

5G NR Unlicensed – NRU

1. Licensed spectrum is the corner stone of wireless-mobile service (coverage/efficiency /reliability).
2. Unlicensed spectrum completements, boosting capacity and improving data connectivity.
3. Access Scenarios:

• Scenario A: Carrier aggregation NR in licensed band (Pcell) and NR-U (Scell)
• Scenario B: Dual connectivity LTE in licensed band (Pcell) and NR-U (PSCell)
• Scenario C: Standalone-NR
• Scenario D: Standalone cell in unlicensed band and UL in licensed band
• Scenario E: Dual connectivity NR in licensed band and NR-U

• FBMC

There’re different proposals Multiple access technique for 5G NR. CP-OFDMA is the one selected at Release 15; however, there are different other MA techniques like Filter Bank Multi Carrier FBMC. There are pros and cons for each one specially from spectrum, power efficiency, and device complexity.

• 5G Beamforming

Advantages of ACTIVE ANTENNA 5G:

1. Improved capacity and reliability: To enable higher system capacity AAS radios will make use of new high-frequency bands from 24GHz up to 42GHz.
2. Higher data rates and lower latency
3. Better connections: Active antenna 5G enables stronger and better connections. Using larger 5G array antennas provides the system additional beamforming to overcome severe propagation challenges that are encountered at mmWave frequency ranges.
4. Less intercell interference: Active antenna 5G will potentially reduce intercell interference experienced in LTE by a large extent.
5. Greater efficiency and better signal coverage enabled by beamforming – In an active antenna 5G system, using beamforming, cells can deliver extremely fast coverage with low latency.
6. Independent optimization per carrier and per technology – Active antenna 5G enables optimization of individual carriers and technologies.

• Carrier Bandwidth Parts

5G NR supports different subcarrier spacing within a carrier. The carrier is then split into carrier bandwidth parts (BWP) of the same subcarrier spacing and CP-length. A carrier bandwidth part is a contiguous set of physical resource blocks, selected from a contiguous subset of the common resource blocks defined for a given numerology µ on a given carrier.

• A Preview of Upcoming 5G RAN Online Training

RAN Solutions to reduce 5G Latency will be included in the upcoming 5G RAN Training that will be on the 7th of September, 2019.

• Voice Over 5G

In this Video, three questions are addressed:

1. Why Voice Over 5G?
2. What are the Benefits of Voice Over 5G?
3. What are the main scenarios/Options for Voice Over 5G?

• Polar Codes in 5G Control Signaling

Why 5G NR uses different codes for data and control?

In order to deliver higher performance and efficiency, 5G NR needs a new channel coding using larger coding block sizes. 5G NR specifies an advanced low-density parity-check (LDPC) for the Data Channel; however, 5G NR uses Polar codes for Control Signaling but why? Because physical control channels typically have small block lengths and here Polar codes are suitable. Also Polar codes are the first to achieve maximum channel capacity, closing the gap to the Shannon limit, and improve performance compared to LTE.

• 5G NR Capabilities

5G NR is the new air interface which will be implemented in multiple phases and releases of 3GPP. 5G use cases such as eMBB, URLLC and mMTC can only be achieved through this new air interface, which has the following key characteristics:

1. Support for large bandwidth to deliver gigabit throughput (mmWaves).
2. Joint operation in lower and upper band.
3. Massive MIMO to increase coverage especially in higher frequency bands by using beamforming.
4. Ultra-lean design to minimize always-on transmission, making the network and devices more efficient.
5. Flexible numerology with subcarrier spacing ranging from 15KHz to 240KHz which will follow a proportional change in cyclic prefix duration.
6. Mini slots transmission to support low latency allowing for immediate transmission of data with very low latency.
7. Dynamic TDD, where (parts of) a slot can be dynamically allocated to either uplink or downlink as part of the scheduler decision to improve latency.

• 5G NR Frame Structure Design Principles

• NOMA Study in Release 16

Study on 5G Non-Orthogonal Multiple Access (NOMA) as a proposal for Multiple access technique for 5G NR, was proposed by ZTE Corporation. 3GPP Release 16 with Acronym: FS NR Noma. The study was Preceding Rel-14 study item which many non-orthogonal multiple-access schemes are evaluated in the Rel-14 NR study item. The benefits of non-orthogonal multiple access for 5G NR, particularly when enabling grant-free transmission, may encompass a variety of use cases or deployment scenarios, including eMBB, URLLC, mMTC etc. In RRC_CONNECTED state, it saves the scheduling request procedure assuming UE is already uplink synchronized.

• 5G Resource Grid

In 5G NR, Resource block contains 12 subcarriers in frequency domain only and no time duration. Unlike 4G, One Resource block contains 12 Sub carriers in frequency domain with 7 OFDM symbols in time domain.

• 5G vs LTE: Main Physical Layer Differences

• 5G UE Identities

• 3GPP 5G Release 16

3GPP Release 15 is complete and yes, this release contains pieces of the standard that can be considered “5G.” But 5G development is not finished. Release 16, sometimes referred to as “Phase 2” of 5G on ITU timelines, will contain standardization for a lot of use cases and scenarios not addressed in Release 15. A few areas of study for Release 16 involve feature expansion. These include increasing support for vertical industries, unlicensed spectrum (NR-U), Integrated Access Backhaul (IAB), and frequencies above 52.6 GHz.

• Low Latency in 5G

Extremely low latency will be achieved by placing data processing servers closer to the network edge. Distributed data centers will host functions where they need to be, closer to the edge of the network to reduce latency. Similarly, the data layer might need to be instantiated closer to the access to improve reliability and response time. 

• 5G Indoor Planning

The indoor 5G network construction will face a series of challenges:

1. Networking on high frequency bands
2. Flexible capacity expansion
3. Reliability
4. Efficient O&M
5. Intelligent operation

In order to overcome these considerable challenges, the construction strategies for indoor 5G target networks must be defined from the following perspectives:

1. Networking strategy: Hierarchical Networking of High, Medium, and Low Frequency Bands for Larger Capacity.
2. MIMO solution selection: Massive MIMO (64T64R) antennas cannot be installed for indoor 5G network coverage.
3. Capacity planning: Available indoor 5G network solutions can be divided into three types: indoor digital distributed base station, passive distributed antenna system, and distributed optical fiber repeater.
4. Network reliability: Indoor 5G network coverage redundancy must be considered and multiple headends must be deployed in areas requiring high reliability.
5. Network O&M, and operation: Visualized O&M for Manageable and Controllable Indoor 5G Networks.