Virtualised and Disaggregated 5G-NR vRAN Architecture

Virtualised and Disaggregated 5G vRAN Architecture Overview : Futureproof vRAN architecture for Next Generation 5G networks

Now in the 5G era, a wide variety of new technologies and services is being introduced. These include LTE-NR Dual Connectivity (EN-DC), NR-NR Dual Connectivity (NR-DC), millimeter wave (mmWave) spectrum, Network Function Virtualisation (NFV), Containerised Network Functions, massive Machine Type Communications (mMTC), Ultra Reliable Low Latency Communication (URLLC), Multi-Access Edge Computing (MEC), Network Slicing and Vertical Services, just to name a few. Here we consider vRAN:

Conventional access systems provide a static network architecture which suffers from some fairly challenging limitations in terms of supporting many of these technologies and services. Consequently, a new 5G access system architecture, referred to as ‘Disaggregated RAN’, aims to overcome many of these challenges by breaking up monolithic network features into smaller components that can be individually re-located
as needed without hindering their ability to work together to provide network services. Virtualisation, on the other hand, transitions each of these functions from dedicated hardware to software components, allowing for flexible scaling, as well as rapid and
continuous evolution, so that networks can meet the evolving demands of new and existing services with minimal impact to CAPEX and OPEX. The new 5G access system architecture has four distinct characteristics which will be described in the following
section along with the benefits provided in comparison with legacy hardware solutions. I.e., CU (Central Unit) / DU (Distributed Unit) split, CU-CP (Control Plane) / CU-UP (User Plane) split, CU virtualisation and DU virtualisation.

Virtualised and disaggregated RAN / vRAN CU / DU Split architecture — Virtualised and disaggregated RAN architecture

1 CU/DU Split Architecture

The gNB is split into a CU and DU for the scalability and DU offloading

In order to overcome an explosion in traffic usage, 5G largely makes use of higher frequency bands than LTE. Doing so introduces challenges in coverage due to the inverse relationship between frequency and cell coverage. Typically, small coverage cells result
in more frequent handovers for mobile users and this risks impacting quality of experience if not appropriately managed. If we can increase the number of cells being managed by each individual base station (gNB), then a greater number of handovers can be handled
through intra-gNB mobility which has a significantly smaller impact than inter-gNB mobility since the device’s anchor point remains the same. By separating this functionality from the Digital Unit (DU) and centralizing it towards the Central Unit (CU), we can increase the
number of cells being managed by each CU, and thus maximize the ratio of intra- vs inter-gNB handovers. At the same time, higher frequency bands also allow the use of wider bandwidth carriers and thus gNBs need considerably more traffic processing capacity
compared to LTE eNBs. Compounding on this, when Dual Connectivity is widely used in 5G networks, devices may connect to two different gNBs, but only one of these (the anchor DU) is responsible for processing the split data streams (via Packet Data Convergence
Protocol, or PDCP). Thus the PDCP load is concentrated on the PDCP anchor DU, which creates a load imbalance and inefficient resource usage between the PDCP anchor DU (over-utilised) and the non-anchor DU (under-utilised). To mitigate this load imbalance, PDCP aggregation needs to be off-loaded to the CU in a more central site where pooling /resource sharing can efficiently handle the task. For these reasons, 5G deployments are best served by a separated CU that is more centrally located from the DU.

vRAN CU (Central Unit)

● Non-Real time processing such as RRC, PDCP is off-loaded to the central site and the RRC, PDCP resource pool is shared between multiple DUs.
● CU can accommodate multiple DUs to build a large scale gNB.
● CU is typically virtualised on a COTS server for the scalability and flexibility.

vRAN DU (Distributed Unit)

● Real time processing such as RLC, MAC, PHY, RF need to remain close to the local site.
● DU is also virtualised on a COTS server for business agility.

2 CU-CP/CU-UP Split Architecture

The gNB-CU is split into CP and UP for flexible dimensioning and topology

The new 5G services based around massive Machine Type Communications (mMTC), Ultra Reliable and Low Latency Communications (URLLC), Fixed Wireless Access (FWA), and new industry verticals will generate unique traffic patterns compared to typical mobile data service.
The Conventional DUs with fixed Control and User Plane (CU/UP) resources, which are typically designed to accommodate such ‘typical mobile data services’, are not well-suited to support the newer traffic patterns. Instead, a more flexible capability to dimension and scale directly in-line the traffic requirements of new types of services is needed. In particular, as Network Slicing and MEC are introduced, the UP should be divisible into multiple entities and allocated wherever needed for optimization of each specific services.

vRAN CU-CP/CU-UP split architecture — CU-CP/CU-UP split architecture

3 CU/DU Virtualisation

The CU and DU are virtualised for the enhanced scalability, flexibility and resource efficiency
Along withthe CU/DU split and CU-CP/CU-UP split, container technology can further enhance scalability, flexibility and resource efficiency.

3-1 CU Virtualisation
Each component in the vCU can have its own flavour (size) for flexible
dimensioning. Traffic loads for control and user planes are balanced
between each plane’s components separately to maximize resource
usage efficiency. Each component can be scaled on-demand or
automatically based on current load status.
3-2 DU Virtualisation
Each component in the vDU can have its own flavour (size) for flexible
dimensioning. DU components can be scaled out if additional cells
are deployed.

vRAN CU virtualization architecture — CU Virtualisation architecture

DU virtualization architecture — DU Virtualisation architecture

Benefits of Virtualised and Disaggregated RAN Architecture

Network evolution through Software upgrade

In traditional, hardware-oriented network solutions, the deployment of new standards, features and services often requires replacement of hardware, particularly when there are changes to lower layer protocols or when there is a need for increased processing capacity.
With Virtualisation of the RAN, in which L1/L2 functions are implemented purely through software, the expensive and time- consuming process of hardware replacement can be avoided. Furthermore, as capacity requirements grow due to increased traffic demand, generic off-the-shelf compute hardware can be added to the resource pool – a much more cost-effective proposition than swapping older proprietary hardware for newer proprietary hardware. The end result is that operators are better able to manage and maximize the
lifecycle of their hardware, match forecasted growth to CAPEX and reduce overall costs of ownership.

Adoption of well-developed IT technologies

By implementation of Network Function Virtualisation, operators can deploy and manage their network utilizing well -developed IT principles such as Software-Defined Networking, life-cycle management and CI/CD to minimize CAPEX and OPEX.

Scalable gNB beyond DU boundary

With a CU/DU split, the gNB can be scaled flexibly from small (single DU size) to large (accommodating multiple DUs, up to 2048 cells), agnostic of DU hardware types for various deployment environment (e.g. rural, dense urban, D-RAN, C-RAN, Small Cell, mmWave). This is in contrast to the conventional DU architecture, which presents limitations on gNB scale based on the capacity of individual DU hardware.

Mobility optimised vRAN architecture

In a conventional aggregated RAN, as users move around the boundary of different cells being served by different gNBs, service quality can often be degraded due to frequent inter-gNB handovers and packet forwarding between DUs. On the other hand, each CU in a disaggregated RAN can accommodate a much larger number of cells for each gNB, and itself becomes the mobility anchor point, greatly reducing the number of anchor point handovers that occur as users move between cells. For users, the key benefit is a noticeably improved quality of experience and more reliable mobility as inter-gNB
handovers and packet forwarding is reduced within the broader CU coverage footprint. When UE moves to neighbor cell, intra-gNB HO of CU/DU split architecture has no RRC/PDCP anchor change, no traffic forwarding during HO procedure and no HO signaling toward the Core Networks compared to inter-gNB HO of conventional DU architecture.

Mobility optimised vRAN CU-DU gNodeB gNB architecture — Mobility optimised architecture

Flexibility in CU-UP deployment

The user plane of CU can be sliced into multiple CU-UPs to support network slicing and multiple CU-UPs can be deployed in independent locations while single CU-CP is deployed in the central site. For the network slicing and MEC scenarios such as low latency services or local-break out applications, CU-UP can be located close to DU while CU-UP for eMBB service remains in central site for the high capacity.

CP/UP independent dimensioning and scaling

With the CP/UP split along with CU virtualisation, CP/UP separated resource allocation and scaling enables to adapt to the traffic patterns which varies according to the services. (FWA, eMBB, mMTC etc.) For 5G network, traffic pattern will be complicated because new services with different usage will introduced. Conventional dimensioning typically designed for mobile service traffic pattern cannot adapt to these various traffic patterns of the new services. For example, mMTC services have high control traffic load and low user traffic load. FWA services have low control traffic load and high user traffic load. Flexible dimensioning and scaling of virtualised and disaggregated RAN well adapted to various traffic patterns can bring resource efficiency as well.

Resource efficiency via resource pooling

In some networks today, a centralised RAN (C-RAN) architecture has been implemented in order to provide benefits in terms of resource pooling, reduce hardware requirements and footprint at the edge and simplify network operations and management overall. However, conventional DUs create a type of hard-limit in the benefit that can be gained from a C-RAN deployment due to the fixed capacity of each DU and the static boundary between each piece of hardware. Through virtualisation of the DU functionality and separation of the network function from the hardware resources it requires, we gain the ability to flexibly allocate and scale resources independently and in a far more granular manner. For example, a conventional DU can experience severe load imbalance in some situations, such as separate DUs assigned between rural and urban areas, or in the case of anchor versus non-anchor DUs in a Dual Connectivity scenario. If we can instead pool the hardware resources independently of each DU function, we can flexibly assign resources to each DU only as needed, mitigating the potential for load imbalance to occur. Overall, this means that fewer resources are required due to gains in statistical multiplexing, i.e. there
is less need to provide emergency overload capacity individually for each DU. The flexible dimensioning and scale in/out features of vRAN which enable efficient resource pooling are described in the following section.

Flexible dimensioning with multiple flavours

The vCU (CU-CP, CU-UP) and vDU consist of several components. Specific components have a flavour set for flexible dimensioning. A flavour defines the amount of resources to support certain capacity or performance. vCU&vDU can be built with various combination of flavours considering required network performance and capacity. This flexible dimensioning based on network virtualisation enables optimization in constructing networks in terms of resources such as CPU core and memory.

Flavour Sets:

Flexible dimensioning with multiple flavours

Automatic/on-demand scale in/out of vCU

According to the each control/user traffic decreases and increases, CP Component and UP Component can be scaled in/out automatically or on-demand manner. This scale in/out enables dynamic resource adaptation to control/user traffic change respectively. Furthermore, because each components share common resources for scaling, resources can be utilised efficiently.

On-demand scale in/out of vDU

As the vDU support on-demand scaling for the DU Component, it does not have to be allocated HW resource of maximum vDU capacity for further network growth at initial deployment stage. Instead, it can start with a number of DU Components only required for the initial deployment. When more cells are required, vDU can increase its cell capacity by scaling-out the DU Component.

L1/L2 acceleration on x86 server

The physical layer and MAC layer of a RAN consist of a set of functions with very high computational complexity: channel estimation and detection, Successive Interference Cancellation (SIC) for MIMO, Forward Error Correction (FEC), scheduling algorithms that handle resource allocation between users with different QoS requirements and channel conditions, and so on. Intel’s Advanced Vector Extension (AVX) instruction set can be applied to many of these functions – especially those related to signal processing that involve vector operations. To further increase the capacity of the vDU, some computation-intensive task with repetitive structures, such as FEC, may be off-loaded to an FPGA, which can be optionally installed into a COTS server via a PCIe interface.

vRAN L1/L2 functions in vDU — L1/L2 functions in vDU

Real time processing technique

User data received from the vCU (i.e. the downlink PDCP packets) passes through a chain of processes in the vDU to become physical layer packets. For successful transmission of these packets over the air, all processing must be completed before the designated time slot begins. Similarly in the uplink, the vDU recovers the information bit stream from the received uplink signals through channel estimation, demodulation and channel decoding, and sends a HARQ feedback to the corresponding user device within the given time budget. In order to meet this timing-stringent operation requirement, L1/L2 tasks in the vDU are carefully designed to be scheduled and completed. IT application software in general show unpredictable response times with a large deviation from the average. The figure below shows how such jittery processing times can affect vDU operation. In the case of conventional task scheduling, generated packets can frequently end up being discarded due to such unexpected delay, degrading link performance due to high packet loss rates.

vRAN Real-time SDR software processing technique — Real-time processing technique

Performance and capacity optimization

The efficient use of compute resources, as well as accelerated packet processing and networking, are crucial for a competitive vRAN design considering the large amount of data that vRAN must handle. One simple way to see this is to compare the fronthaul
bandwidth to the user traffic rate. For example, in 16-QAM, just four bits of user data turns into a pair of I/Q samples composed of about 20 bits to ensure reasonable performance in a noisy, fading channel. In essence, vRAN needs a much higher packet handling capability
for the radio-side interface than its backhaul interface. To get the best performance and capacity from x86-based COTS servers, our vRAN adopts various virtualisation techniques, including core pooling and pinning, DPDK and SR-IOV.

Telco grade reliability and availability

We note that in modern societies, it is easy to identify a growing reliance on communications across a variety of sectors, including business, finance and public safety. If a mobile communication service becomes unavailable for even a short period of time, serious collateral damage can result in terms of social disorder and monetary losses. To avoid such chaotic outcomes, each component of a network must maintain a high standard of telco-grade service availability and reliability – and the vRAN is no exception to this. Basic fault recovery and redundancy features commonly available in the IT domain are no sufficient. Our vRAN applies enhanced or newly designed health checks, fault recovery and geo-redundancy techniques to minimize service outages.

Introduction of Virtualised DU in 5G Networks

Virtualised DU for Network Slicing

Through network slicing, 5G networks can effectively and efficiently provide a wide variety of different service types (e.g., eMBB, URLLC, mMTC, etc.) in a given cell. Each network slice has its own service and performance requirement profile. For example, URLLC requires very low millisecond-scale latency and very high reliability in comparison to eMBB, where latency and reliability requirements or more relaxed but bandwidth is a key concern. In the case of mMTC on the other hand, individual traffic volumes are much lower, but
reliable device density is of prime importance. 5G networks must be capable of efficiently allocating hardware and radio resources for each of these separate services on a per-slice basis. While a traditional DU may be effective in the deployment of a large number
of high-bandwidth, wideband NR cells thanks to the high performance of dedicated hardware technologies such as application-specific integrated circuits (ASICs), as networks begin to target more diverse service types virtualised DUs capable of flexibly adapting to customised traffic profiles will prove to be a valuable and cost-efficient approach.

VRAN Virtualized DU for network slicing — Virtualised DU for network slicing

DU Separation for Secure Network Slice

Some network slice could need dedicated DUs separated from existing DUs to serve services like eMBB. For example, a security service could need extremely high security level to need separate DU not to eavesdrop traffic packets. In the following diagram, on top
of existing NR network, Virtualised DU is deployed for secure service slice. You can notice that RU is shared between two DUs through common layer.

VRAN DU separation for security network slice — DU separation for security network slice

Conclusions

The widely deployed distributed RAN was designed nearly 20 years ago in the pre-smartphone 3G era, when few would have foreseen the incredible volume and variety of traffic, devices, and applications that mobile networks carry today. While this outdated architecture has evolved to more centralised models, current solutions do not go far enough to address CSP challenges.
CSPs are under pressure to keep up with surging traffic demand and the influx of new devices and applications, while at the same time finding additional service revenue to stabilise ARPU and cut costs to protect profit margins.
By extending the benefits of NFV from the core network to the RAN, virtualised RAN is the optimal solution for cost-efficiently increasing capacity, reducing costs, and creating new services.
Various vendors have joined forces to create a pre-integrated solution that CSPs can deploy today to start reaping the benefits. The solution delivers carrier grade reliability and predictable performance, low-latency, unrivaled manageability and orchestration, massive scalability, optimised resource utilisation, and flexible deployment options as well as
the ability to quickly launch new services through network slicing and service chaining. The pre-integrated vRAN solution and comprehensive professional services mitigate deployment risk and accelerate time-to-market.

For Further Information

Please Contact Us

July 27, 2020July 27, 2020

5G Disaggregated Network Topology Split Options

Functional Split Options for gNodeB 5G-NR Base Stations

A major benefit of 5G for Mobile Network Operators (MNOs) is the prospect of migrating from custom network nodes to a far more flexible approach that enables network nodes to be implemented in software running on generic hardware platforms. In the core network, this process is in an advanced state, with virtualisation and orchestration techniques from the IT world now being used to deploy network functions automatically at a large scale. The functional “split” is key to achieving efficiency gains.

The process is significantly more difficult in the RAN and backhaul network, and the prize for MNOs is greater here as these functions typically account for 70-80% of Capex. In Release 15, the 3GPP identified various functional splits in the 5G NR RAN gNodeB (base station) that would facilitate this process, identifying eight possible places where the gNodeB function could be split into separate functional units. The most popular of these “split” options are:

Split 0 – gNodeB Integrated Small Cell

*The gNodeB is a traditional integrated 5G NR with the RF, PHY and stack layers integrated into a single unit, with an NG interface to the 5GC Core Network.*

Split 2 – 3GPP F1

The 3GPP defines this disaggregated RAN with separate (gNodeB-)CU and (gNodeB-)DU units with a high level split 2 using the 3GPP defined F1 interface. Split 2 is sometimes used in conjunction with a lower level splits 6, 7.2 and 8. This new 3GPP 5G RAN architecture introduces new terminology, interfaces and functional modules.

Split 6 – Small Cell Forum (SCF) nFAPI

*The split 6 interface protocol is the Network FAPI (nFAPI), specified by the Small Cell Forum, where the MAC and PHY functions are physically separate.*

Split 7.2 – O-RAN Open Fronthaul

*A split 7 interface has been specified by the O-RAN Alliance, which has adopted the eCPRI interface as its basis. Whereas CPRI passes antenna samples using a proprietary protocol, eCPRI uses Ethernet.*

Split 8

Industry Body Backed Split Option Definitions

3GPP specified the higher layer F1 interface, but additional interfaces at lower layer splits have also been specified by other industry bodies, and offer different relative advantages and disadvantages.

The Split 6 interface protocol is the Network FAPI (nFAPI), specified by the Small Cell Forum, where the MAC and PHY functions are physically separate.
The Split 7 interface has been specified by the O-RAN Alliance, which has adopted the eCPRI interface as its basis. Whereas CPRI passes digitised RF signals to the antenna using a proprietary serial protocol, eCPRI uses Ethernet. Moreover, in O-RAN fronthaul, it is frequency domain samples that are transported between the upper PHY and lower PHY, which leads to advantages.
The Split 8 interface is mainly being considered where there are legacy systems and existing hardware and cabling/fibre can be reused.

For Further Information

Please Contact Us

July 24, 2020July 24, 2020

5G Dynamic Spectrum Sharing (DSS)

5G with Dynamic Spectrum Sharing (DSS) is a game-changer

Wireless Service Providers can tap spectrum currently used for 4G to launch nationwide 5G coverage with a simple network software upgrade, and deploy a “5G Ready” network to operate on 4G today, with easy upgrade to 5G without disruption.

What is Dynamic Spectrum Sharing (DSS)?

Dynamic Spectrum Sharing (DSS) is emerging as a key part of mobile service providers’ 5G strategy. Using cellular base stations with DSS offers the lowest total cost of ownership (TCO) to launch 5G in bands currently used for 4G – enabling nationwide 5G coverage in short time after launch. Dynamic Spectrum Sharing allows an existing LTE carrier to operate 5G New Radio (NR) and LTE simultaneously – with a simple software upgrade. The solution is based on innovative intelligent scheduler algorithms that enable optimal performance as the mix of 4G and 5G devices in the network changes over time.

From the early stages of research into 5G NR, when developers began to map 5G transmissions to time-frequency resources, the developers created the possibility for holes in the 5G transmission grid which could be used for 4G LTE transmissions. This means that, by simultaneously sharing frequency bands which are already available today, service providers can fire up 5G on existing LTE bands without actually shutting off LTE. This means that, as well as having the option to roll out 5G on existing DSS-compatible 4G hardware, operators can keep the LTE network up and running while starting 5G. This can make it far easier for operators to transition to 5G in the coming years.

How does DSS work?

The 5G physical layer is designed to be so similar to 4G in 3GPP that DSS becomes feasible with the same subcarrier spacing and similar time domain structure. DSS is designed to be backwards compatible with all existing LTE devices. communication service providers (CSPs) therefore need to maintain LTE cell reference signal (CRS) transmission. 5G transmission is designed around LTE CRS in an approach called CRS rate matching.

Dynamic Spectrum Sharing (DSS) for 4G and 5G — Picture credit – Nokia

DSS with 5G carrier aggregation (CA) releases the full potential of the technology, especially when combined with standalone (SA) architecture. CA provides the highest data rates while SA maximizes low-band coverage and access to 5G services. DSS will be supported by a growing number of 5G devices from 2020 onwards, with widespread support for devices with DSS, SA and CA available during the course of 2021. The
introduction of DSS capability therefore aligns with the growing availability of devices

One option is for DSS to use a single shared baseband card for 4G and for 5G, which obviously precludes a multi-vendor solution for 4G and 5G. The other option is to keep the existing 4G baseband and add a new 5G baseband. The scheduling between the two baseband functions is then based on a fast Xp interface between 4G and 5G. This interface is not open and works only for a single vendor, so CSPs must use the same vendor in 4G and 5G if they use DSS

Dynamic Spectrum Sharing (DSS) for 4G to 5G Upgrade — Diagram credit – Nokia

Conclusions

DSS is a great solution for flexibly refarming spectrum to 5G. Operators can build a “5G ready” network today, operating in 4G, and switch over partially – or fully – to 5G at any later date, without losing back-compatibility for 4G device users

For Further Information

Please Contact Us

July 3, 2020July 3, 2020

5G NR Frame Structure

Exploring the 5G NR Frame Structure used in 5G New Radio networks and 5G Radio equipment: including gNodeB and 5G CPE devices

Frame Structure

The 5G NR frame structure is defined by the 3GPP and here we present details of the NR Frame Structure that is specified in 3GPP specification (38.211).

Numerology – Subcarrier Spacing

Compared to LTE numerology (subcarrier spacing and symbol length), the most outstanding difference you can notice is that NR support multiple different types of subcarrier spacing (in LTE there is only one type of subcarrier spacing, 15 KHz). The types NR numerology is summarized in 38.211 and I converted the table into illustration to give you intuitive understanding of these numerology.

As you see here, each numerology is labeled as a parameter(u, mu in Greek). The numerology (u = 0) represents 15 kHz which is same as LTE. And as you see in the second column the subcarrier spacing of other u is derived from (u=0) by scaling up in the power of 2.

Numerology and Slot Length

As illustrated below, Slot length gets different depending on numerology. The general tendency is that slot length gets shorter as subcarrier spacing gets wider. Actually this tendency comes from the nature of OFDM. You would see further details on how the slot length is derived in Radio Frame Structure section.

Numerology and Supported Channels

Not every numerology can be used for every physical channel and signals. That is, there is a specific numerologies that are used only for a certain type of physical channels even though majority of the numerologies can be used any type of physical channels. Following table shows which numerologies can be used for which physical channels.

< 38.300-Table 5.1-1: Supported transmission numerologies and additional info.>

OFDM Symbol Duration

Parameter / Numerlogy (u)	0	1	2	3	4
Subcarrier Spacing (Khz)	15	30	60	120	240
OFDM Symbol Duration (us)	66.67	33.33	16.67	8.33	4.17
Cyclic Prefix Duration (us)	4.69	2.34	1.17	0.57	0.29
OFDM Symbol including CP (us)	71.35	35.68	17.84	8.92	4.46

Numerology – Sampling Time

Sampling time can be defined differently depending on Numerogy (i.e, Subcarrier Spacing) and in most case two types of Timing Unit Tc and Ts are used.

Tc = 0.509 ns
Ts = 32.552 ns

See Physical Layer Timing Unit page to see how these numbers are derived and to see some other timing units.

Radio Frame Structure

As described above, in 5G/NR multiple numerologies(waveform configuration like subframe spacing) are supported and the radio frame structure gets a little bit different depending on the type of the numerology. However, regardless of numerology the length of one radio frame and the length of one subfame is same. The length of a Radio Frame is always 10 ms and the length of a subframe is always 1 ms.

What changes to accommodate the physical property of the different numerology ? Answer is to put different number of slots within one subfame. There is another varying parameter with numerology. It is the number of symbols within a slot. However, the number of symbols within a slot does not change with the numerology, it only changes with slot configuration type. For slot configuration 0, the number of symbols for a slot is always 14 and for slot configuration 1, the number of symbols for a slot is always 7.

Now look at details of radio frame structure for each numerology and slot configuration:

< Normal CP, Numerology = 0 >

In this configuration, a subframe has only one slot in it, it means a radio frame contains 10 slots in it. The number of OFDM symbols within a slot is 14.

< Normal CP, Numerology = 1 >

In this configuration, a subframe has 2 slots in it, it means a radio frame contains 20 slots in it. The number of OFDM symbols within a slot is 14.

< Normal CP, Numerology = 2 >

In this configuration, a subframe has 4 slots in it, it means a radio frame contains 40 slots in it. The number of OFDM symbols within a slot is 14.

< Normal CP, Numerology = 3 >

In this configuration, a subframe has 8 slots in it, it means a radio frame contains 80 slots in it. The number of OFDM symbols within a slot is 14.

< Normal CP, Numerology = 4 >

In this configuration, a subframe has 16 slots in it, it means a radio frame contains 160 slots in it. The number of OFDM symbols within a slot is 14.

< Extended CP, Numerology = 2 >

In this configuration, a subframe has 8 slots in it, it means a radio frame contains 80 slots in it. The number of OFDM symbols within a slot is 12.

Slot Format

Slot Format indicates how each of symbols within a single slot is used. It defines which symbols are used for uplink and which symbols are used for downlink within a specific slot. In LTE TDD, if a subframe (equivalent to a Slot in NR) is configured for DL or UL, all of the symbols within the subframe should be used as DL or UL. But in NR, the symbols within a slot can be configured in various ways as follows.

We don’t need to use every symbols within a slot (this can be a similar concept in LAA subframe where only a part of subframes can be used for data transmission).
Single slot can be devided into multiple segments of consecutive symbols that can be used for DL , UL or Flexible.

Theoretically we can think of almost infinite number of possible combinations of DL symbol, UL symbol, Flexible Symbol within a slot, but 3GPP allows only 61 predefined symbol combination within a slot as in following table. These predefined symbol allocation of a slot called Slot Format. (For the details on how these Slot Format is being used in real operation, refer to Slot Format Combination page).

<38.213 v15.7 -Table 11.1.1-1: Slot formats for normal cyclic prefix>

D : Downlink, U : Uplink, F : Flexible

Symbol Number in a slot

Format

62-254

Reserved

255

UE determines the slot format for the slot based on tdd-UL-DL-ConfigurationCommon, or tdd-ULDL-ConfigurationDedicated and, if any, on detected DCI formats

Why we need so many different types of slot formats ? Key goal is to make NR scheduling flexible especially for TDD operation. By applying a slot format or combining different slot formats in sequence, we can implement various different types of scheduling as in the following example:

TDD DL/UL Common Configuration

See TDD DL/UL Common Configuration page.

Resource Grid

The resource grid for NR is defined as follows. If you just take a look at the picture, you would think it is almost identical to LTE resource grid. But the physical dimension (i.e, subcarrier spacing, number of OFDM symbols within a radio frame) varies in NR depending on numerology.

The maximum and minimum number of Resource blocks for downlink and uplink is defined as below (this is different from LTE)

< 38.211 v1.0.0 Table 4.4.2-1: Minimum and maximum number of resource blocks.>

Following is the table that I converted the downlink portions of Table 4.4.2-1 into frequency Bandwidth just to give you the idea on what is the maximum RF bandwidth that a UE / gNB need to support for single carrier.

u	min RB	Max RB	sub carrier spacing(kHz)	Freq BW min(MHz)	Freq BW max(MHz)
0	24	275	15	4.32	49.5
1	24	275	30	8.64	99
2	24	275	60	17.28	198
3	24	275	120	34.56	396
4	24	138	240	69.12	397.44

SS/PBCH

SS(PSS and SSS) and PBCH in NR is transmitted in the same 4 symbol block as specified in the following table.

< Frequency Domain Resource Allocation >

Overall description on the resource allocation for SS/PBCH block is described in 38.211 – 7.4.3.1 Time-frequency structure of an SS/PBCH block and followings are the summary of the specification.

SS/PBCH block consists of 240 contiguous subcarriers (20 RBs)
The subcarriers are numbered in increasing order from 0 to 239 within the SS/PBCH block
The UE may assume that the contents(value) of the resource elements denoted as ‘Set to 0’ in Table 7.4.3.1-1 are set to zero. (This mean that the contents of the gray colored resource element in the SSB diagram shown below is filled with zeros).
k_ssb corresponds to the gap between Subcarrier 0 of SS/PBCH block and Common Resource Block
- is obtained from the higher-layer parameter OffsetToPointA
- offset-ref-low-scs-ref-PRB corresponds to the FrequencyInfoDL.absoluteFrequencyPointA. Data type is ARFCN-ValueNR and the range of the value is INTEGER (0..3279165) in integer.
There are two types of SS/PBCH Block
- Type A (Sub 6)
  - k_ssb(k0 in older spec) = {0,1,2,…,23}
    - 4 LSB bits of k_ssb value can informed to UE via ssb-subcarrierOffset in MIB
    - The MSB bit is informed to UE via a bit within the PBCH Data ()
    - is expressed in terms of 15 Khz subcarrier spacing
  - u (numerology) = {0,1}, FR1 (sub 6 Ghz)
  - is expressed in terms of 15 Khz subcarrier spacing
- Type B (mmWave)
  - k_ssb(k0 in older spec) = {0,1,2,…,11}
    - the whole k_ssb value can be informed to UE via ssb-subcarrierOffset in MIB
    - is expressed in terms of the subcarrier spacing provided by the higher-layer parameter subCarrierSpacingCommon in MIB .
  - u (numerology) = {3,4}, FR2 (mmWave)
  - is expressed in terms of 60 Khz subcarrier spacing

NOTE : Actually understanding k_ssb and in the resource grid often get confusing and hard to visualize. The following is an example where the SubcarrierSpacingCommon is equal to 30KHz, and k_ssb=2, where in such a case the center of the first subcarrier of the SS/PBCH Block (which has 15KHz SCS) coincides with the center frequency of the subcarrier 1 of

This table can be represented in Resource Grid as shown below. Note that the position of PBCH DM-RS varies with v and the value v changes depending on Physical Cell ID.

< Time Domain Resource Allocation >

Following table indicates the first OFDM symbol number (s) where SS/PBCH is transmitted. This is based on 38.213 – 4.1 Cell Search.

The document states as follows :

For a half frame with SS/PBCH blocks, the number and first symbol indexes for candidate SS/PBCH blocks are determined according to the subcarrier spacing of SS/PBCH blocks as follows.

This means that [38.213 – 4.1 Cell Search] specifies SS/PBCH location in time domain as illustrated below.

< Start Symbols for each subcarrier spacing and frequency >

Followings are examples of SSB Transmission for each cases. For the simplicity, I set the frequency domain location of SSB block to be located at the bottom of the system bandwidth, but in reality the frequency domain location can change to other location (e.g, center frequency of the system bandwidth). The main purpose of these examples is o show the time domain location (transmission pattern) of each cases. In real deployment, it is highly likely (but not necessarily) that the frequency domain location of the SSB located around the center frequency.

The example below shows how you can correlate the above table to the SSB transmission plot shown in the following examples.

For Further Information

For more information about 5G NR Frame structure used in 5G Radios:

Please Contact Us

June 19, 2020June 19, 2020

SIM cards for 5G:

5G SIM cards: What’s changed for 5G?

Do the new security and privacy features of 5G require a new SIM card? Simple answer is no. However, the complete answer is more complex.

SIM cards are Smart Cards with data

In this article, we refer to these newer smart cards as Rel 99+ USIM which are compatible with 3GPP Release 1999 (first 3G specifications) and afterwards. These Rel 99+ USIMs can be used to access every generation of mobile networks, including 5G. Such backward and forward compatibility is achieved by the carefully-designed offloading of some computations and storage to mobile phones.

While accessing the 5G system is one thing, the question we have is whether using the “new” security and privacy features of 5G requires a new kind of USIM other than Rel 99+ USIMs which could be used for 4G security. This is a valid question and something which we address below. For the sake of brevity, in this post, we do not touch upon other new features in 5G that do not concern USIM.

SIM Identity and access management (IdaM)

In 5G, subscription permanent identifier (SUPI) could be in two formats, one is the legacy format called international mobile subscriber identity (IMSI) and another is the format newly adopted in 5G called network access identifier (NAI). Furthermore, 5G provides at least two methods of authentication and key agreement (AKA) for accessing the network. One such method, 5G AKA, is an evolution of the authentication method in 4G. Another, called EAP-AKA’, is a method now widely adopted in 5G for broader use of the Extensible Authentication Protocol (EAP) framework.

In any case, from the IdaM viewpoint, the Rel 99+ USIMs that could be used in 4G are still compatible with 5G, in that they can be used to authenticate and gain access to the 5G system. The main reason for this forward compatibility is the fact that there is no need for a new permanent security key shared between USIMs and the network. Another reason is that newer storage and computations required for new security features can be offloaded to mobile phones, like the calculation of a new type of AKA response and new session keys.

The adoption of the EAP framework in 5G means that it is possible for other methods than EAP-AKA’, such as Extensible Authentication Protocol-Transport Layer Security (EAP-TLS), to be used for isolated deployments. In those cases, it could be such that the USIM’s role is skipped. It is also worth noting that, just as with 4G networks, any smart cards older than Rel 99+ USIM (which may be called Rel 98- SIM) cannot be used to access 5G.

5G SIM Privacy

5G has introduced significant privacy enhancements in terms of how permanent and temporary identifiers are used.

An important topic which is use of subscription concealed identifier (SUCI). The SUCI, which basically hides the SUPI over-the-air, can be calculated using standardized schemes like so-called Profile A and Profile B. It also requires some new parameters like public key of the home network, scheme identifier, and routing indicator. While SUCI calculations using Profile A/B can be offloaded to mobile phones, the standards only permit the storage of the new parameters in the USIM. For brevity, in this post we will not discuss the proprietary option where SUCI calculation can be done in USIMs using non-standardized schemes.

Therefore, Rel 99+ USIMs can be used to store the parameters required for SUCI calculation with Profile A/B given that they support creating the necessary files (DF5GS/EFSUCI_Calc_Info/EFRouting_Indicator). This is also true for Rel 99+ USIMs already in the field i.e. if they support some mechanisms like remote file management over-the-air (OTA), then they could be used for storing the parameters required for SUCI calculation with Profile A/B. Otherwise, SUCI will be calculated by mobile phones using the so-called “null-scheme” which is a dummy scheme and does not hide SUPI. In other words, Rel 99+ USIMs that cannot store new parameters required for SUCI calculation could still be used to get access to the 5G system but without the ability to hide the SUPI over-the-air.

Note that there are also other privacy enhancements in 5G like the strict refreshment of temporary identifiers, decoupling of permanent identifiers from paging procedures, and partial confidentiality protection of initial messages. For these features, the USIM’s role is not required in the standards.

Steering of roaming (SoR) and UE parameter update (UPU)

SoR and UPU are two new procedures in 5G between mobile phones and the home network. These new procedures enable the home network to update configuration parameters in mobile phones and/or USIM using control plane signaling. It means that, in 5G, the home network has an alternative to existing mechanisms like over-the-air (OTA) updates that use SMS as transport.

As well as handling of the so-called “secured packet” that mobile phones can basically relay to the USIM, the scope of SoR and UPU procedures include parameters like operator controlled PLMN selector with access technology, default configured network slice selection assistance information (NSSAI), and routing indicator.

Handling of new control plane signaling including security, like calculation and verification of new security tokens, are offloaded to mobile phones. Furthermore, in some cases, storage of parameters is also offloaded to mobile phones like default configured NSSAI and mobile phone’s copy of operator controlled PLMN selector with access technology. Therefore, in such cases, special support from the USIM is not required for SoR and UPU in 5G, which means that Rel 99+ USIMs can be used.

There are other cases when the storage of the new/updated parameters is still done in USIM, like routing indicator (EFRouting_Indicator), USIM’s copy of operator controlled PLMN selector with access technology (EFOPLMNwACT), and any file handling done by the “secured packet”. Even then, Rel 99+ USIMs are still compatible with SoR and UPU in 5G given that they support the necessary file management operations.

5G SIM card Summary

To summarize, impacts on USIMs by relevant security and privacy features that are new in 5G.

from IdaM viewpoint, Rel 99+ USIMs which could be used for 4G are still compatible to get access in 5G.
Regarding SUPI privacy, Rel 99+ USIMs can be used to enable SUCI calculation with Profile A/B as long as they support necessary file management operations. Regarding other privacy features, Rel 99+ USIMs are fully compatible in their current form.
From a perspective of SoR/UPU procedures, Rel 99+ USIMs are compatible in their current form only in some cases, while in other cases compatibility will depend on them supporting necessary file management operations.
Whether/how to use the above mentioned new security and privacy features is in the remit of the network operator and therefore, even in worst case, they will not prohibit access to the plethora of other basic 5G features.

Technical notes

IdaM part – The formats of SUPI (IMSI and NAI) are defined in 3GPP TS 23.003, see clauses 2.2A, 2.2, and 28.7.2. The new type of AKA response is called RES* and new session keys are called KAUSF and KSEAF. See clauses 6.1 in 3GPP TS 33.501 for details. In Annex B of that TS, you will also find details of using EAP-TLS
Privacy part – The formats of SUCI are defined in clauses 2.2B and 28.7.3 in 3GPP TS 23.003. Clause 6.12 and Annex C in 3GPP TS 33.501 contain main details of subscription identifier privacy. Clause 4.4.11 in 3GPP TS 31.102 specifies USIM files specific to 5G
SoR/UPU part – The new security tokens are called SoR-MAC-IAUSF, UPU-MAC-IAUSF, SoR-MAC-IUE, and UPU-MAC-IUE. See the main details of SoR and UPU can be found in clauses 6.14 and 6.15 in 3GPP TS 33.501, Annex C in TS 23.112, and Clause 4.20 in TS 23.502

For Further Information

Please Contact Us

June 4, 2020June 5, 2020

5G beamforming, beam steering and beam switching with massive MIMO

Beamforming, Beam Steering & Beam Switching with Massive MIMO for 5G compared

Combining the high propagation loss of the millimeter wavelengths (mmWaves) employed in 5G new radio (5G NR) systems, plus the higher bandwidth demands of users, combinations of beamforming techniques and massive Multiple Input and Multiple Output (MIMO) are essential for increasing spectral efficiencies and providing cost-effective, reliable wireless network coverage.

Beamforming

Beamforming is the application of multiple radiating elements transmitting the same signal at an identical wavelength and phase, which combine to create a single antenna with a longer, more targeted stream which is formed by reinforcing the waves in a specific direction. The general concept was first employed in 1906 for trans-oceanic radio communications.

With more radiating elements that make up the antenna, the narrower the beam. An artifact of beamforming is side lobes. These are essentially unwanted radiation of the signal that forms the main lobe in different directions. Poor engineering of antenna arrays would result in excessive interference by a beamformed signal’s side lobe. The more radiating elements that make up the antenna, the more focused the main beam is and the weaker the side lobes are.

Beamforming, Beam Steering, Beam Switching, Massive MIMO for 5G

Figure 1: Beamforming with two and four radiating elements

While digital beamforming at the baseband processor is most commonly used today, analog beamforming in the RF domain can provide antenna gains that mitigate the lossy nature of 5G millimeter waves.

Beam steering and beam switching

Beam steering is achieved by changing the phase of the input signal on all radiating elements. Phase shifting allows the signal to be targeted at a specific receiver. An antenna can employ radiating elements with a common frequency to steer a single beam in a specific direction. Different frequency beams can also be steered in different directions to serve different users. The direction a signal is sent in is calculated dynamically by the base station as the endpoint moves, effectively tracking the user. If a beam cannot track a user, the endpoint may switch to a different beam.

Figure 2: Beam steering and beam switching

This granular degree of tracking is made possible by the fact that 5G base stations must be significantly closer to users than previous generations of mobile infrastructures.

Massive MIMO

Multiple input and multiple output (MIMO) antennas have long been a feature of commercial public wireless and Wi-Fi systems, but 5G demands the application of massive MIMO. To increase the resiliency (signal-to-noise ratio / SNR) of a transmitted signal and the channel capacity, without increasing spectrum usage, a common frequency can be steered simultaneously in multiple directions.

The successful operation of MIMO systems requires the implementation of powerful digital signal processors and an environment with lots of signal interference, or “spatial diversity”; that is a rich diversity of signal paths between the transmitter and the receiver.

Figure 3: Multiple input and multiple output (MIMO)

Diversity of arrival times, as the signal is bounced from different obstacles, forms multiple time-division duplexing (TDD) channels that can deliver path redundancy for duplicate signals or increase the channel capacity by transmitting different parts of the modulated data. First conceived of in the 1980s, there are a few differences between classic multi-user MU-MIMO and Massive MIMO, but fundamentally it is still the large number of antennas employed and the large number of users supported. The degree of MIMO is indicated by the number of transmitters and the number of receivers, i.e. 4×4.

Conclusion

Beamforming, Beam Steering, Beam Switching and Massive MIMO are key ingredients for 5G base stations.

For Further Information

Please Contact Us

April 24, 2020April 27, 2020

Safety of 5G Frequencies and Networks

Is 5G Safe? Why do some people think it isn’t?

There’s currently huge controversy in the news today regarding safety of 5G: Is it safe, or not? 5G vendors & scientists say the technology is perfectly safe, and some members of the public allege that 5G isn’t safe. Here we examine the topics factually.

Frequencies used by 5G

There is nothing magic or new about the frequencies used or proposed for 5G. They have ALL been used already, actually for decades! 5G frequencies are split into two sections: FR1 (less than 6GHz) and FR2 (high frequency microwave, or “millimeter wave”).

Almost ALL of the FR1 frequencies have already been used for 4G, and some before that for 3G, and 2G, back to the 1990’s. A good example is 900MHz (the original GSM system) and 1800MHz (second round of GSM). 2100MHz was used extensively for 3G. A few of the FR1 frequencies haven’t been used for 4G before (e.g. 3800 up to 4200MHz) but they have been used for other purposes before.

FR2 frequencies (millimeter wave, or mmWave) have already been used – very widely – for Point-to-Point microwave links. All of the FR2 bands (24Ghz, 26GHz, 28GHz, 38-40GHz, and even the proposed 60GHz) have been used for point-to-point terrestrial microwave links. Those are the parabolic dishes you see everywhere on rooftops or towers. These signals are highly directional “pencil beams” with typically 1 degree or less beam width. The number of these links globally is in the 100,000+ range: they are beaming signals around cities all over the world, usually connecting internet services, beaming signals up to 3G/4G towers or for links between corporate office networks. As a result of the creation of 5G technology, these frequencies are now being re-used (“re-farmed”) for use by 5G base stations to connect end users to the internet, using Point-to-multipoint beamforming technologies. Important note: the use of 5G is no more or less “scary” than the previous use for point to point links. Note that point-to-point microwave has existed since 1930: 90 years ago, and health risks (and lack of risk to public) are very well understood.

Operating Distances

5G in lower frequencies travels longer distances than higher frequencies, due to laws of physics. This is why the lower frequencies are used for Rural locations for wide area coverage, whereas the higher frequencies are reserved for use in cities, where distances are shorter, and user densities higher.

Also, the lower frequencies (lower end of FR1) can be transmitted at higher power levels than the higher frequencies. Conversely, high frequencies (mmWave, FR2) are limited to lower power due to limitation of today’s commercial technology.

5G in the 24GHz, 26GHz, 28GHz range and above (also called millimeter wave, or mmWave bands) uses higher frequencies than 4G. As a result, these high frequency 5G signals are not capable of traveling large distances (over a few hundred meters), unlike 4G or lower frequency 5G signals (sub 6 GHz) so penetration and hence coverage are lower.
This higher frequency therefore requires placing 5G base stations every few hundred meters in order to use higher frequency bands.

5G and RF power levels

Some of the “5G Conspiracists” allege that 5G will cause damage/health risk to humans. There is simply no measured case or evidence of this happening. If there were, there would be scientists & health advisors demanding change. Let’s examine in more detail:

5G sites using FR1 transmit at exactly the SAME power levels as 4G sites. So you’re not irradiated any more than a 4G site was. 40W a typical figure for a macro (big) site, and 1W for a Small Cell (small site).
Note carefully: 5G FR1 sites use EXACTLY the same power levels as 4G sites, which is similar to 3G sites, and before that, 2G sites …
5G uses “sector antennas” (typically 3 on a macro site) just like 4G does.
Therefore any related health risk is therefore the same for 5G as it’s predecessors.

5G sites using FR2 transmit at MUCH lower power levels: less than 1 Watt typically. These high frequency signals have poor penetration of buildings and obstacles, so are generally “line of sight” only. As noted above, ALL of the FR2 frequencies have been used before, for terrestrial microwave links, and at similar power levels (less than 1 Watt).
The use of beamforming steers the signal to the required locations; this reduces the overall amount of transmitted power emitted into the air, and hence total radiation. Put simply, if you aren’t using your device, the base station doesn’t point power at you.

How to 5G power levels compare to other Radio/RF transmitters?

The VERY good question conspiracists & “truthers” never discuss. Let’s go straight there.

A TV transmitter such as Crystal Palace in London, UK currently transmits digital terrestrial Television at over 1200kW (1.2 MEGAWATT, or 1,200,000 watts), and has been transmitting TV since 1956. That is 120 MILLION TIMES more power than a V-band 60GHz radio, and transmitting for over 60 years. Did you hear “5G protesters” complaining about TV transmitters? No, because there’s no widespread history of health effects over 60 years .
Airport Radars: To keep planes flying safely, airport radars transmit pulses up to 25kW (25 kilowatts, or 25,000 Watts) into the air, with average power 2.1kW (2100 Watts). Interestingly, these signals are at similar frequencies to 3G, 4G and 5G. In the USA, 2.7 – 2.9 GHz is used. Yet nobody complains about these high power levels of radar, which has been in constant use since the 1930s: 90 years.
Digital Radio (DAB): Crystal Palace transmits digital radio with 18kW (18,000 Watts) of radio power. Compare that with 40W of a large (macro) 5G base station.
Emergency Service (TETRA) Radios : used by police, fire & ambulances: transmit at up to 45 Watts. Very similar to the 40W of a large (macro) 5G base station.

You will notice that the HIGHEST powered transmitters are Television transmitters (Megawatt), Radars & Radio stations (10’s of Kilowatts). A macro 5G base station at 40W comes nowhere close. Note that these various transmitters are used on different frequencies, there’s no “one” frequency that is safer (or less safe) than another. It’s only the RF exposure (power) level that matters – specifically, the power incident on your own human body.

Why is there no mass hysteria from “Truthers” about TV, Radar and Radio transmitters? Because if they were THAT bad for our health, they would have been banned and switched off decades ago. Evern the largest (macro) 5G transmit powers are tiny by comparison.

Key “Truther” points examined:

60GHz is absorbed by Oxygen in the bloodstream (Untrue)
Out in the open air this absorption is true : but not in the body! 60GHz signals are 40% reflected by skin surface, absorbed by water (body is 60% water), and does NOT enter the bloodstream. The “Truthers” invent Pseudo-science , claiming: “This causes Oxygen to not bind well to blood hemoglobin causing the body to become Oxygen starved (hypoxia)” This statement is hopelessly unscientific. The ultra low power 60GHz signals do not even penetrate human skin. The signals are partly reflected and partly absorbed by the skin, preventing them entering the body and cannot cause the claimed effect. There is NO scientific study which will back up this claimed hypoxia effect on the human body. The “5G protesters” NEVER provide any, because there is no publication or science that would agree with their unscientific claims – it’s simply not impossible. They make stuff up to make you afraid, and sharing their website gives them more “hits”: Some have adverts on their sites. More clicks means more money for them! (Fear=money for some)
5G is a state-sponsored weapon: Untrue.
5G is simply a marketing term applied to the work of the 3GPP, a standards body which includes equipment vendors & operators, as a linear development of from work that was labelled 4G and 3G before it. Governments are not included in developing 2G, 3G, 4G, 5G… and future 6G technology – corporations are.
Governments want to use 5G to control the population: Untrue,
in that 5G gives Government agencies no more data than 4G does. Your location, digital activities, content & data usage habits are already well known to Google, Facebook and – on warrant – Law Enforcement Agencies. 5G does not change this at all. You already gave all that data to companies 10 years ago when you bought a 3G smartphone, or signed up with Social Media sites, apps, Apple or Google services. Law enforcement agencies can demand access to that data with a warrant.
IoT is scary: Untrue, in any way that relates to 5G.
“Internet of Things” is a marketing label applied to home gadgets – and industrial devices – that are connected via the Internet by either WiFi or cellular (4G, 5G) networks. The same IoT label applies to a WiFi doorbell. Main concern with IoT is DATA security, particularly physical security (locks, cars) and CCTV camera feeds. That has nothing to do with 5G, because the concern is the data security of the devices & security attitudes of companies that sell them. Note that the WiFi-connected IoT devices are a much greater security risk than 4G, 5G because WiFi is much easier for criminals to hack/spoof.
5G causes cancer: Untrue.
5G uses the same signals as 4G (FR1), plus some millimeter wave frequencies (FR2) which were previously used by microwave links for decades. There is no link to cancer in 30+ years of medical research and continued exposure to these signals. Microwave & radio signals used by 4G & 5G are NON-ionising radiation which is not hazardous except in massively high power levels (far more than 4G, 5G etc). The “dangerous” radiation type is IONISING radiation, including X-rays and similar. Those are not used for communication for this exact reason: they are dangerous.
(Side-note: X-Rays used in medicine are VERY carefully controlled. Had an X-Ray? note the operators have shielding everywhere, because they use it every day & could get higher does than patients. They regulate the dose to you carefully for your safety)
5G is linked to Coronavirus: Untrue.
There’s no link at all. Many of the countries with terrible cases of Coronavirus have no 5G. And vice versa. All the theories connecting the two have been soundly debunked by reputable & international scientists.
(Side note: there IS a link between Coronavirus deaths and air pollution: because the Coronavirus effect on the body attacks the lungs, putting patients with poor respiration are at great risk. Cleaning up diesel emissions, industrial cities & banning smoking would have saved 1000’s of lives from Coronavirus.)

Power levels and Distance (very important topic)

The RF power emitted from the transmitter antenna spreads with distance. This means that a person some distance away from the tower only receives a weak signal. As you DOUBLE the distance, you receive one QUARTER the power level. This is called the “inverse square law”. What it means in practice is that a person 100’s of metres away from a base station is radiated with only microwatts of power, which is insignificant, especially compared to this next point:

The highest radiation of Radio signals you will get is from …. wait for it …
Your cellphone is on your person – and when used in the worst case, held directly against your head. The cellphone transmits at up to 1 Watt power – in all directions – which means the signals go into your head as well as the air around you. This topic remains the same since the first cordless phones in the 1980’s, analogue cellphones and GSM phones in the 1990’s. Using the phone means the signal is close to your head – and the most sensitive item, your brain. The HIGHEST amount of radiation you will receive from any wireless system is from your OWN HANDSET when you hold it to your head to make a voice call. Therefore, if you are really worried about cellphone safety – STOP using your OWN phone. The radiation your body receives from it is 1000’s of times stronger than that you receive from the mast.

If you’re worried about 2G, 3G, 4G, 5G masts: stop now. The FIRST thing you must do is switch off your OWN phone, and never hold it against your head to talk. And if it’s in your pocket/jacket/handbag do remember, it’s still transmitting to the mast, updating it’s location to the network, and often up/downloading data to your apps continually. It’s still transmitting, even in “standby”.
If you’re not prepared to turn off your OWN PHONE, then stop worrying about masts at all. The signal from masts signal is over 1000 times weaker than your OWN PHONE when it reaches your body.

5G FR2 mmWave Penetration

Also, these higher frequency 5G signals cannot penetrate solid objects easily, such as cars, trees, and walls, because of the nature of these higher frequency electromagnetic waves. 5G cells can be deliberately designed to be as inconspicuous as possible, which finds applications in places like restaurants and shopping malls.

Cell types 5G NR FR2	Deployment environment	Max. number of users	Output power (mW)	Max. distance from base station
Femtocell	Homes, businesses	Home: 4–8 Businesses: 16–32	indoors: 10–100 outdoors: 200–1000	10s of meters
Pico cell	Public areas like shopping malls, airports, train stations, skyscrapers	64 to 128	indoors: 100–250 outdoors: 1000–5000	10s of meters
Micro cell	Urban areas to fill coverage gaps	128 to 256	outdoors: 5000−10000	few hundreds of meters
Metro cell	Urban areas to provide additional capacity	more than 250	outdoors: 10000−20000	hundreds of meters
Wi-Fi (for comparison)	Homes, businesses	less than 50	indoors: 20–100 outdoors: 200–1000	few 10s of meters

5G NR mmWave FR2 coverage

Challenges for 5G Safety – for EVERYONE !

It is the responsibility of the 4G/5G cellular industry, national regulators, safety agencies and all academics to be truthful about the safety of all radio transmitters. There must be no cover-ups, lying, or partial truths. Medical research into possible risks of RF exposure must continue and be well funded. The industry needs to deliver reliable cellullar service without putting populations at risk. “Profit” cannot come at cost of public safety.

Conversely – “truthers” making up pseudo-science & invented “facts”, with blogs written by uneducated persons have so far resulted in:

Violence and threats against telecom employees doing their jobs on sites
4G/5G sites being burned down (resulting in loss of service to Hospitals, including those treating Coronavirus and critical health conditions)
Death threats and threats of violence against business owners.

Now think clearly and rationally: EVERYONE has a legal & moral responsibility to behave within the law and not to threaten the health of others.
Clearly those posting non-factual “truther” content on Internet websites & social medahave a responsibility to bear. If you are one of those authors, think carefully. Your action could well cause harm or death of others.

I simply don’t believe you!

That’s the frequent response of someone when confronted with information that conflicts with their previously held opinion or prejudices. In the case of 5G, we have we have plenty of information sources. On the “5G is safe” side we have:

All reputable Scientists Worldwide
All national Governments
Biologists Worldwide
All safety Agencies Worldwide
The Cellphone industry
30+ years of no measurable health effects of cellphones on worldwide population

And on the “5G is unsafe” side we have:

Conspiracists without facts
Non-scientific blog writers, some whom earn $ from adverts on their blogs (!)
Narcissists who want “likes” on posts, or TV appearances
Easily-swayed but highly opinionated people
NO evidence of health effects over 30+ years
NO reputable scientists !

Have a careful think about what sources of information you take in forming your world view. Just two hundred years ago, our ancestors burned and drowned innocent people for “witchcraft”. Why are we any better informed than our ancestors? Answer: SCIENCE and EDUCATION. We use logic, rather than irrational and uninformed fear.

Conclusion for 5G & Safety

There is a huge media frenzy and “truther sites” full of pseudo-science about 5G & safety. We suggest we make our decisions based on science and facts. Here’s our summary:

5G is no less safe than 4G. If you didn’t protest 4G, stop protesting 5G.
(If you DID protest 4G, then carry on protesting, but remember, 5G is no less safe!)
“Millimeter wave” frequencies have already been used for 3 decades or more for terrestrial microwave links. We’ve already been irradiated by them for 30+ years, with no harm to us. 5G just re-uses these same frequencies.
There is no measured health risk from “Millimeter Wave” signals in any credible study or publication. 60GHz doesn’t stop O2 in the blood, that’s a non-scientific myth invented by “truther” blogs. No medical reports or science to back up claims.
“Millimeter wave” (FR2) transmitters are on average 50x less powerful than the lower frequency FR1 macro (main site) transmitters.
The HIGHEST radiation you will get is from your OWN cellphone: it’s right next to your body, and transmits even in your pocket/jacket/handbag. If you’re worried, turn it off.
Turning off 5G transmitters on masts makes AlMOST NO DIFFERENCE because the 2G, 3G, 4G transmitters on the mast are still transmitting, all at very similar power levels and frequencies, and distance to you is the same. Power levels radiated to your body remains almost unchanged whether you turn 5G on or off.
Turning OFF all the cellphone masts will cause deaths. A LOT of them, as your loved ones can’t dial an ambulance, lost persons, persons caught in fires & crash victims can’t call help. Emergency responders also rely on the masts. Conversely, there’s no measured death rate from cellphone masts, in over 40 years of widespread use.
LOGIC as well as ETHICS says leave the masts turned on.

For Further Information

If you are interested in 5G Health & Safety:
Please Contact Us

April 6, 2020April 6, 2020

5G Coverage using FR2 mmWave frequencies

5G FR2 Coverage and Penetration

5G FR2 mmWave Penetration

5G mmWave FR2 Penetration and Coverage — Diagram courtesy Qualcomm

Cell types 5G NR FR2	Deployment environment	Max. number of users	Output power (mW)	Max. distance from base station
Femtocell	Homes, businesses	Home: 4–8 Businesses: 16–32	indoors: 10–100 outdoors: 200–1000	10s of meters
Pico cell	Public areas like shopping malls, airports, train stations, skyscrapers	64 to 128	indoors: 100–250 outdoors: 1000–5000	10s of meters
Micro cell	Urban areas to fill coverage gaps	128 to 256	outdoors: 5000−10000	few hundreds of meters
Metro cell	Urban areas to provide additional capacity	more than 250	outdoors: 10000−20000	hundreds of meters
Wi-Fi (for comparison)	Homes, businesses	less than 50	indoors: 20–100 outdoors: 200–1000	few 10s of meters

5G NR mmWave FR2 coverage

Challenges for 5G Coverage:

Transmissions in mmWave bands suffer from significantly higher path loss and susceptibility to blockage. In addition, mmWave RF complexity makes meeting the cost and power constraints of mobile devices extremely challenging, which is why mmWave for mobile communications has historically been not feasible—until now. 5G NR mmWave is changing this.

Uses for 5G mmWave

While the initial focus for mobile operators is to quickly expand network capacities by starting deployments of 5G NR mmWave in existing dense urban markets, there are even more opportunities for mmWave beyond traditional macro networks. One area of interest is to bring mmWave indoors to address the exploding demand of fiber-like wireless broadband access in crowded venues, such as convention centers, concert halls, and stadiums. These venues have traditionally been challenged with limited network capacity, thereby constrained with the quality of service (e.g., slow speeds and unreliable connectivity) they can deliver. With mmWave’s significantly wider bandwidth and high spatial multiplexing gains, mobile operators and service providers could rapidly make multi-Gigabit, low-latency connectivity available to a large number of users.

Another exciting opportunity for mmWave is for private indoor enterprises, including offices, shop floors, meeting rooms and more. Imagine having virtually unlimited capacity and fiber-like wireless connectivity for your devices at work, no matter if it’s a smartphone, tablet, laptop, or mobile extended reality (XR). For these indoor deployment scenarios, we have also performed extensive study to show that significant coverage (i.e., >90%) and multi-Gbps median speeds can be achieved simply by co-siting mmWave small cells with existing LTE or Wi-Fi access points.

For Further Information

If you are interested in 5G Deployment Solutions:
Please Contact Us

April 1, 2020April 1, 2020

Massive MIMO and Beamforming in 5G

Massive MIMO (mMIMO) and beamforming are key acronyms widely used in the telecom industry when referring to 5G and latest advancements of 4G LTE. We note that MIMO comes in many different variants, some of them having been in use already for years in today’s 4G LTE networks.

SU-MIMO vs. MU-MIMO

In 4G LTE, the term MIMO usually refers to Single User MIMO (SU-MIMO). In Single User MIMO, both the base station and UE have multiple antenna ports and antennas, and multiple data streams are transmitted simultaneously to the UE using same time/frequency resources, doubling (2×2 MIMO), or quadrupling (4×4 MIMO) the peak throughput of a single user.

In MU-MIMO, base station sends multiple data streams, one per UE, using the same time-frequency resources. Hence, MU-MIMO increases the total cell throughput, i.e. cell capacity. The base station has multiple antenna ports, as many as there are UEs receiving data simultaneously, and one antenna port is needed in each UE.

Beamforming: principles of operation

The terms beamforming and mMIMO are sometimes used interchangeably. One may consider that beamforming is used in mMIMO, or beamforming is a subset of mMIMO. In general, beamforming uses multiple antennas to control the direction of a wave-front by appropriately weighting the magnitude and phase of individual antenna signals in an array of multiple antennas. That is, the same signal is sent from multiple antennas that have sufficient space between them (at least ½ wavelength). In any given location, the receiver will thus receive multiple copies of the same signal. Depending on the location of the receiver, the signals may be in opposite phases, destructively averaging each other out, or constructively sum up if the different copies are in the same phase, or anything in between. Beamforming is further divided to subcategories as explained in the following chapters.

Digital beamforming (Baseband beamforming, precoding)

In this scenario, the signal is pre-coded (amplitude and phase modifications) in baseband processing before RF transmission. Multiple beams (one per each user) can be formed simultaneously from the same set of antenna elements. In the context of LTE/5G, MU-MIMO equals to digital beamforming. Multiple TRX chains, one per each simultaneous MU-MIMO user, are needed in the base station. Digital beamforming (MU-MIMO) is used in LTE Advanced Pro (transmission modes 7,8, and 9) and in 5G NR. Digital beamforming improves the cell capacity as the same PRBs (frequency/time resources) can be used to transmit data simultaneously for multiple users.

Analog beamforming

Here, the signal phases of individual antenna signals are adjusted in RF domain. Analog beamforming impacts the radiation pattern and gain of the antenna array, thus improves coverage. Unlike in digital beamforming, only one beam per set of antenna elements can be formed. The antenna gain boost provided by the analog beamforming overcomes partly the impact of high pathloss in mmWave. Therefore analog beamforming is considered mandatory for the mmWave frequency range 5G NR.

Hybrid beamforming

Hybrid beamforming combines the analog beamforming and digital beamforming. It is expected that mm-wave gNB (5G base station) implementations will use some form of hybrid beamforming. One approach is to use analog beamforming for coarse beamforming, and inside the analog beam use a digital beamforming scheme as appropriate, either MU-MIMO or SU-MIMO.

Massive MIMO

Most common definitions are that mMIMO is a system where the number of antennas exceeds the number of users. In practice, massive means there are 32 or more logical antenna ports in the base station It is expected that NEMs will start with a maximum of 64 logical antenna ports in 5G.

This diagram illustrates how mMIMO works in practice. An antenna array of 50 omni elements, with ½ wavelength spacing in between the antenna elements is used. The 50 elements transmit 4 distinct streams of data via 4 logical antenna ports, one stream for each UE. All four streams are transmitted using the same physical resource blocks, i.e. the same time/frequency resources. The data streams do not interfere between each other because each of them has a distinct radiation pattern, where the signal strength in the direction of the target UE is optimized, and in the directions of the other UEs (victim UEs) the signal strength is minimized.

In MU-MIMO/mMIMO, the base station applies distinct precoding for the data stream of each UE where the location of the UE, as well as the location of all the other UEs, are taken into account to optimize the signal for target UE and at the same time minimize interference to the other UEs. To do this, the base station needs to know how the downlink radio channel looks like for each of the UEs.

For Further Information

Please Contact Us

March 31, 2020March 31, 2020

CPRI and eCPRI in 5G and open vRAN

CPRI, eCPRI and open vRAN: What’s happening?

Common Public Radio Interface (CPRI) has been around for quite some time. But now, enhanced CPRI (eCPRI) is becoming an important technology to understand for 5G.

Before looking in detail at eCPRI, it’s helpful to understand some of the basic topology of the cellular network, which currently uses CPRI.

CPRI, Remote Radio Heads (RRH) in 4G and 5G

At the outer circle of a cellular network topology, remote radio units (RRUs) are distributed every few miles in cities and suburban areas. These RRUs comprise antennas and also some compute functionality.

Fiber runs from a cluster of these RRUs to connect to a more centralized baseband unit. The baseband unit is also sometimes called the “central processing unit.” Baseband units are typically distributed within approximately 10-mile circles for good coverage in populated areas. The connection between the RRUs and the base station is often referred to as “fronthaul.”

eCPRI

CPRI is an interface that sends data from the RRUs to the baseband unit: CPRI is a serial interface, which is a very high-speed connection, a way to translate all those radio signals back to the computing function.

As we go to 5G, the fiber between the RRUs and the baseband unit is going to carry much more traffic, and that makes it more difficult to do a serial interface. Extreme 5G requirements are stretching the limits of fiber bandwidth.

Enter eCPRI, which is a way of splitting up the baseband functions and putting some of that functionality in the RRU to reduce the burden on the fiber.

AT&T is among many carriers that are working on eCPRI. AT&T has made “the world’s first” eCPRI connection for mmWave at its 5G Labs in Redmond, Washington. AT&T made calls testing eCPRI, using systems from both Nokia and Samsung Electronics America.

This opens the door for higher network throughput with less fiber, which will create more efficient mmWave deployments, among other benefits, This is also a significant step in creating an open architecture within the radio access network (RAN).

Vendor lock-in

Another problem with the CPRI interface today is that it has become a proprietary technology.

In addition to supporting more bandwidth across fewer fibers, the enhanced CPRI also addresses the proprietary concerns. eCPRI will be an open interface, making it easier for carriers to mix and match vendor equipment for their RRUs and their baseband units.

Historically, because each vendor would have its own implementation of CPRI, it became proprietary. This forces carriers to buy both their RRUs and their baseband unit from the same vendor in order for the interface to work. With O-RAN this interface will be open. Carriers such as AT&T who implement eCPRI will be able to run equipment from different vendors, or even generic off-the-shelf equipment.

However, existing networks with CPRI installed will most likely remain in place for years to come.

For Further Information

To find out more about CPRI and eCPRI, please Contact Us