Skip to main content

Integrated Access and Backhauling (IAB) - Today and Tomorrow

I wrote a detailed blog on The 3G4G Blog late last year about what IAB is and what will be available this year as part of Release-16 and what enhancements are planned as part of Release-17. It's available here.

In the Ericsson Technology Review last month, there is a short section on IAB which is reproduced below for anyone wishing to dig deep into this topic:
IAB provides an alternative to fiber backhaul by extending NR to support wireless backhaul. As a result, it is possible to use NR for a wireless link from central locations to distributed cell sites and between cell sites. This can simplify the deployment of small cells, for example, and be useful for temporary deployments for special events or emergency situations. IAB can be used in any frequency band in which NR can operate. However, it is anticipated that mm-wave spectrum will be the most relevant spectrum for the backhaul link. Furthermore, the access link may either operate in the same frequency band as the backhaul link (known as inband operation) or by using a separate frequency band (out-of-band operation).

Architecture-wise, IAB is based on the CU/DU split introduced in release 15. The CU/DU split implies that the base station is split into two parts – a centralized unit (CU) and one or more distributed units (DUs) – where the CU and DU(s) may be physically separated depending on the deployment. The CU includes the RRC (radio resource control) and PDC (packet data convergence) protocols, while the DU includes the RLC (radio link control) and MAC (multiple access control) protocols along with the physical layer. The CU and DU are connected through the standardized F1 interface.

Figure 2 illustrates the basic structure of a network utilizing IAB. The IAB node creates cells of its own and appears as a normal base station to UEs connecting to it. Connecting the IAB node to the network uses the same initial-access mechanism as a terminal. Once connected, the IAB node receives the necessary configuration from the donor node. Additional IAB nodes can connect to the network through the cells created by an IAB node, thereby enabling multi-hop wireless backhauling.

The lower part of the figure highlights that an IAB node includes a conventional DU part that creates cells to which UEs and other IAB nodes can connect. The IAB node also includes a mobile-termination (MT) part providing connectivity for the IAB node to (the DU of) the donor node.

PDF of the magazine is available here.
Ericsson also provides a good summary in RP-190971 regarding Release 16 IAB and Rel-17 enhancements:
  • IAB Rel-16 provide basic support for multi-hop and multi-path relaying. 
  • The solution supports 
    • QoS prioritization of traffic on the backhaul link
    • Flexible resource usage between access and backhaul
    • Topology adaptivity in case link failure
  • In Rel-17 it would be possible to further evolve the IAB solution targeting increased efficiency and support for new use cases
Related Posts:


Popular posts from this blog

High-level Architecture Introduction of Mobile Cellular Networks from 2G to 5G

Here is an old tutorial explaining high level mobile network architecture, starting from GSM and then looking at GPRS, UMTS, LTE & 5G. Slides and video below High-level architecture of Mobile Cellular Networks from 2G to 5G from 3G4G Related links : Free 2G, 3G, 4G & 5G Training Videos 5G (IMT-2020) Wireless 5G vs 4G: what is the difference?

5G Connectivity will Enable New Use Cases

While we have been discussing advanced 5G use cases for years, it is only now, with the Standalone 5G (5G SA) that it is going to become possible to have many of these in practice. Of course they will take time to mature and be popular with the end users. As a part of our Free 5G Training initiative , we made a short video that will provide you with ideas and motivation for why 5G could do a lot more than just faster speeds. The video is embedded below. In addition, Parallel Wireless, one of the companies I consult for, did a webinar on 5G Use Cases which is available here . A good webinar on BrightTALK on 5G Use Cases by @Parallel_tw - #Free5Gtraining #5G #5GNetworks #5GUseCases #5GSpectrum #eMBB #mMTC #URLLC #5GRoadmaps #OpenRAN #5GXR #FWA #Vodafone #TMobile #Healthcare — 5G Training (@5Gtraining) May 28, 2020 Let us know which one is your favorite and which ones do you think will make operators money.

Fixed Wireless Access (FWA) and the Path to 5G Wireless Wireline Convergence (WWC)

I have covered Fixed Wireless Access (FWA) on The 3G4G Blog here and looked at automated HetNet design which included FWA links here . I have also covered Wireline Wireless Convergence (WWC) as part of 5G and Fixed-Mobile Convergence (FMC) posts. The links to the posts are available at the end. Back in December, Juniper took part in a Light Reading webinar which is being shared as part of this post. With revenues flat and traffic continuing to explode, the unsustainable state of network economics needs another disruption. The 5G deployment cycle offers an insertion opportunity for new converged architectures. Wireless offload solutions can re-route the traffic of data-hogging mobile subscribers over wireline cores built for bandwidth and performance rather than mobile cores (EPC) primarily designed for mobility and portability. The 5G Network Architecture in 3GPP Release-16 allows the convergence of fixed and wireless networks. This also allows many new opportunities as can be se