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Showing posts with label AT&T. Show all posts
Showing posts with label AT&T. Show all posts

Saturday, 15 April 2017

Self-backhauling: Integrated access and backhaul links for 5G


One of the items that was proposed during the 3GPP RAN Plenary #75 held in Dubrovnik, Croatia, was Study on Integrated Access and Backhaul for NR (NR = New Radio). RP-17148 provides more details as follows:

One of the potential technologies targeted to enable future cellular network deployment scenarios and applications is the support for wireless backhaul and relay links enabling flexible and very dense deployment of NR cells without the need for densifying the transport network proportionately. 

Due to the expected larger bandwidth available for NR compared to LTE (e.g. mmWave spectrum) along with the native deployment of massive MIMO or multi-beam systems in NR creates an opportunity to develop and deploy integrated access and backhaul links. This may allow easier deployment of a dense network of self-backhauled NR cells in a more integrated manner by building upon many of the control and data channels/procedures defined for providing access to UEs. An example illustration of a network with such integrated access and backhaul links is shown in Figure 1, where relay nodes (rTRPs) can multiplex access and backhaul links in time, frequency, or space (e.g. beam-based operation).

The operation of the different links may be on the same or different frequencies (also termed ‘in-band’ and ‘out-band’ relays). While efficient support of out-band relays is important for some NR deployment scenarios, it is critically important to understand the requirements of in-band operation which imply tighter interworking with the access links operating on the same frequency to accommodate duplex constraints and avoid/mitigate interference. 

In addition, operating NR systems in mmWave spectrum presents some unique challenges including experiencing severe short-term blocking that cannot be readily mitigated by present RRC-based handover mechanisms due to the larger time-scales required for completion of the procedures compared to short-term blocking. Overcoming short-term blocking in mmWave systems may require fast L2-based switching between rTRPs, much like dynamic point selection, or modified L3-based solutions. The above described need to mitigate short-term blocking for NR operation in mmWave spectrum along with the desire for easier deployment of self-backhauled NR cells creates a need for the development of an integrated framework that allows fast switching of access and backhaul links. Over-the-air (OTA) coordination between rTRPs can also be considered to mitigate interference and support end-to-end route selection and optimization.

The benefits of integrated access and backhaul (IAB) are crucial during network rollout and the initial network growth phase. To leverage these benefits, IAB needs to be available when NR rollout occurs. Consequently, postponing IAB-related work to a later stage may have adverse impact on the timely deployment of NR access.


There is also an interesting presentation on this topic from Interdigital on the 5G Crosshaul group here. I found the following points worth noting:

  • This will create a new type of interference (access-backhaul interference) to mitigate and will require sophisticated (complex) scheduling of the channel resources (across two domains, access and backhaul).
  • One of the main drivers is Small cells densification calling for cost-effective and low latency backhauling
  • The goal would be to maximize efficiency through joint optimization/integration of access and backhaul resources
  • The existing approach of Fronthaul using CPRI will not scale for 5G, self-backhaul may be an alternative in the shape of wireless fronthaul

Let me know what you think.

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Friday, 24 February 2017

Connecting Rural Scotland using Airmasts and Droneways


This week EE has finally done a press release on what they term as Airmasts (see my blog post here). Back in Nov. last year, Mansoor Hanif, Director of Converged Networks and Innovation BT/EE gave an excellent presentation on connecting rural Scottish Islands using Airmasts and Droneways at the Facebook TIP Summit. Embedded below are the slides and video from that talk.





In other related news, AT&T is showing flying COWs (Cell On Wheels) that can transmit LTE signals


Their innovation blog says:

It is designed to beam LTE coverage from the sky to customers on the ground during disasters or big events.
...
Here’s how it works. The drone we tested carries a small cell and antennas. It’s connected to the ground by a thin tether. The tether between the drone and the ground provides a highly secure data connection via fiber and supplies power to the Flying COW, which allows for unlimited flight time.  The Flying COW then uses satellite to transport texts, calls, and data. The Flying COW can operate in extremely remote areas and where wired or wireless infrastructure is not immediately available. Like any drone that we deploy, pilots will monitor and operate the device during use.

Once airborne, the Flying COW provides LTE coverage from the sky to a designated area on the ground.  

Compared to a traditional COW, in certain circumstances, a Flying COW can be easier to deploy due to its small size. We expect it to provide coverage to a larger footprint because it can potentially fly at altitudes over 300 feet— about 500% higher than a traditional COW mast.  

Once operational, the Flying COW could eventually provide coverage to an area up to 40 square miles—about the size of a 100 football fields. We may also deploy multiple Flying COWs to expand the coverage footprint.

Nokia on the other hand has also been showcasing drones and LTE connectivity for public safety at D4G Award event in Dubai


Nokia's Ultra Compact Network provides a standalone LTE network to quickly re-establish connectivity to various mission-critical applications including video-equipped drones. Drones can stream video and other sensor data in real time from the disaster site to a control center, providing inputs such as exact locations where people are stranded and nature of the difficulty of reaching the locations.

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Monday, 16 January 2017

Gigabit LTE?


Last year Qualcomm announced the X16 LTE modem that was capable of up to 1Gbps, category 16 in DL and Cat 13 (150 Mbps) in UL. See my last post on UE categories here.


Early January, it announced Snapdragon 835 at CES that looks impressive. Android central says "On the connectivity side of things, there's the Snapdragon X16 LTE modem, which enables Category 16 LTE download speeds that go up to one gigabit per second. For uploads, there's a Category 13 modem that lets you upload at 150MB/sec. For Wi-Fi, Qualcomm is offering an integrated 2x2 802.11ac Wave-2 solution along with an 802.11ad multi-gigabit Wi-Fi module that tops out at 4.6Gb/sec. The 835 will consume up to 60% less power while on Wi-Fi."

Technology purists would know that LTE, which is widely referred to as 4G, was in fact pre-4G or as some preferred to call it, 3.9G. New UE categories were introduced in Rel-10 to make LTE into LTE-Advanced with top speeds of 3Gbps. This way, the ITU requirements for a technology to be considered 4G (IMT-Advanced) was satisfied.


LTE-A was already Gigabit capable in theory but in practice we had been seeing peak speeds of up to 600Mbps until recently. With this off my chest, lets look at what announcements are being made. Before that, you may want to revisit what 4.5G or LTE-Advanced Pro is here.

  • Qualcomm, Telstra, Ericsson and NETGEAR Announce World’s First Gigabit Class LTE Mobile Device and Gigabit-Ready Network. Gigabit Class LTE download speeds are achieved through a combination of 3x carrier aggregation, 4x4 MIMO on two aggregated carriers plus 2x2 MIMO on the third carrier, and 256-QAM higher order modulation. 
  • TIM in Italy is the first in Europe to launch 4.5G up to 500 Mbps in Rome, Palermo and Sanremo
  • Telenet in partnership with ZTE have achieved a download speed of 1.3 Gbps during a demonstration of the ZTE 4.5G new technology. That's four times faster than 4G's maximum download speed. Telenet is the first in Europe to reach this speed in real-life circumstances. 4.5G ZTE technology uses 4x4 MIMO beaming, 3-carrier aggregation, and a QAM 256 modulation.
  • AT&T said, "The continued deployment of our 4G LTE-Advanced network remains essential to laying the foundation for our evolution to 5G. In fact, we expect to begin reaching peak theoretical speeds of up to 1 Gbps at some cell sites in 2017. We will continue to densify our wireless network this year through the deployment of small cells and the use of technologies like carrier aggregation, which increases peak data speeds. We’re currently deploying three-way carrier aggregation in select areas, and plan to introduce four-way carrier aggregation as well as LTE-License Assisted Access (LAA) this year."
  • T-Mobile USA nearly reached a Gigabit and here is what they say, "we reached nearly 1 Gbps (979 Mbps) on our LTE network in our lab thanks to a combination of three carrier aggregation, 4x4 MIMO and 256 QAM (and an un-released handset)."
  • The other US operator Sprint expects to unveil some of its work with 256-QAM and massive MIMO on Sprint’s licensed spectrum that pushes the 1 gbps speed boundary. It’s unclear whether this will include an actual deployment of the technology

So we are going to see a lot of higher speed LTE this year and yes we can call it Gigabit LTE but lets not forget that the criteria for a technology to be real '4G' was that it should be able to do 1Gbps in both DL and UL. Sadly, the UL part is still not going Gigabit anytime soon.

Friday, 23 September 2016

5G New Radio (NR), Architecture options and migration from LTE


You have probably read about the demanding requirements for 5G in many of my blog posts. To meet these demanding requirements a 'next-generation radio' or 'new radio' (NR) will be introduced in time for 5G. We dont know as of yet what air interface, modulation technology, number of antennas, etc. for this NR but this slide above from Qualcomm gives an idea of what technologies will be required for this 5G NR.
The slide above gives a list of design innovations that will be required across diverse services as envisioned by 5G proponents.

It should be mentioned that Rel-10/11/12 version of LTE is referred to as LTE-Advanced and Rel-13/14 is being referred to as LTE-A Pro. Rel-15 will probably have a new name but in various discussions its being referred to as eLTE.

When first phase of 5G arrives in Rel-15, eLTE would be used for access network and EPC will still be used for core network. 5G will use NR and eventually get a new core network, probably in time for phase 2. This is often referred to as next generation core network (NGCN).

The slides below from Deutsche Telekom show their vision of how operators should migrate from eLTE to 5G.



The slides below from AT&T show their vision of LTE to 5G migration.



Eiko Seidel posted the following in 3GPP 5G standards group (i recommend you join if you want to follow technical discussions)


Summary RAN1#86 on New Radio (5G) Gothenburg, Sweden

At this meeting RAN1 delegates presented and discussed numerous evaluation results mainly in the areas of waveforms and channel coding.

Nonetheless RAN1 was not yet prepared to take many technical decisions. Most agreements are still rather general. 

First NR terminology has been defined. For describing time structures mini-slots have been introduced: a mini-slot is the smallest possible scheduling unit and smaller than a slot or a subframe.

Discussions on waveforms favored filtered and windowed OFDM. Channel coding discussions were in favor of LDPC and Turbo codes. But no decisions have been made yet.

Not having taken many decisions at this meeting, RAN1 now is behind its schedule for New Radio.
Hopefully the lag can be made up at two additional NR specific ad hoc meetings that have been scheduled for January and June 2017.

(thanks to my colleague and friend Dr. Frank Kowalewski for writing this short summary!)

Yet another post from Eiko on 3GPP RAN 3 on related topic.

The RAN3 schedule is that in February 2017 recommendations can be made for a protocol architecture.  In the meeting arguments came up by some parties that the work plan is mainly addressing U-Plane architecture and that split of C- and U-plane is not considered sufficiently. The background is that the first step will be dual connectivity with LTE using LTE RRC as control plane and some companies would like to concentrate on this initially. It looks like that a prioritization of features might happen in November timeframe. Beside UP and CP split, also the functional split between the central RAN node and the distributed RAN node is taking place for the cloud RAN fronthaul interface. Besides this, also discussion on the fronthaul interface takes place and it will be interesting to see if RAN3 will take the initiative to standardize a CPRI like interface for 5G. Basically on each of the three interfaces controversial discussion is ongoing.

Yet another basic question is, what is actually considered as a “New 5G RAN”? Is this term limited to a 5G eNB connected to the NG core? Or can it also be also an eLTE eNB with Dual Connectivity to 5G? Must this eLTE eNB be connected to the 5G core or is it already a 5G RAN when connected to the EPC? 

Finally, a slide from Qualcomm on 5G NR standardization & launch.


Sunday, 12 June 2016

AT&T's 5G Trials


There was a news recently that "AT&T 5G trials expand, break 10 Gbps throughput". The article said:

Austin, Texas, where RCR Wireless News and Industrial IoT 5G Insights is headquartered, is where AT&T worked with the Federal Communications Commission to get an experimental license to conduct 5G technology trials using spectrum in the 3.4-3.6 GHz, 3.7-4.2 GHz, 14.5-15.35 GHz and 27.5-28.5 GHz bands. The carrier said the testing would be used for “experimental equipment” in support of “potential (5G) multi-gigabyte per second applications for fixed and mobile wireless communication networks at higher transmission rates and lower latency than is currently available,” and supporting voice, video and data.
...
“We’ve seen great results in our 5G lab trials, including reaching speeds above 10 gigabits per second in early tests with Ericsson,” said Tom Keathley, SVP of wireless network architecture and design at AT&T. “Nokia is joining to help us test millimeter wave, which we expect to play a key role in 5G development and deployment. The work coming out of AT&T Labs will pave the way toward future international 5G standards and allow us to deliver these fast 5G speeds and network performance across the U.S.”

Here is a presentation with some more details on what AT&T has been up to:



While I have seen speed records being set, this will not be of much help in the final standards. Some of you may remember my earlier post where Huawei achieved over 100Gbps in their labs. See here.

xoxoxoxo Added 27/06/2016:17.00 oxoxoxox

A video of a similar presentation is embedded below: