Monday, 22 July 2019

6G: Above 100 GHz and Terahertz (THz) Frequencies

A new research paper  "Wireless Communications and Applications Above 100 GHz: Opportunities and Challenges for 6G and Beyond" by T. S. Rappaport et al. is available on IEEE website here.

With 5G, we are still solving the challenges of millimeter waves (mmWaves) so it is surprising for most people to hear that there is a research going on beyond 100 GHz and in THz frequencies. Quoting from the abstract of the paper:

The paper describes many of the technical challenges and opportunities for wireless communication and sensing applications above 100 GHz, and presents a number of promising discoveries, novel approaches, and recent results that will aid in the development and implementation of the sixth generation (6G) of wireless networks, and beyond. It also shows recent regulatory and standard body rulings that are anticipating wireless products and services above 100 GHz and illustrates the viability of wireless cognition, hyper-accurate position location, sensing, and imaging. The paper also presents approaches and results that show how long distance mobile communications will be supported to above 800 GHz since the antenna gains are able to overcome air-induced attenuation, and present methods that reduce the computational complexity and simplify the signal processing used in adaptive antenna arrays, by exploiting the Special Theory of Relativity to create a cone of silence in over-sampled antenna arrays that improve performance for digital phased array antennas. Also, new results that give insights into power efcient beam steering algorithms, and new propagation and partition loss models above 100 GHz are given, and promising imaging, array processing, and position location results are presented. The implementation of spatial consistency at THz frequencies, an important component of channel modeling that considers minute changes and correlations over space, is also discussed. This paper offers the first in-depth look at the vast applications of THz wireless products and applications and provides approaches for how to reduce power and increase performance across several problem domains, giving early evidence that THz techniques are compelling and available for future wireless communications.


At Brooklyn 5G Summit 2019, NYU Wireless founder and director, Dr. Ted Rappaport, presented a keynote on his vision beyond 5G, looking at both electronics and photonics, considering applications over 100GHz, channel models, and said that he expects brain-comparative data rate transmission wirelessly over the air in future networks. The keynote is embedded as video above.

Another keynote by Gerhard Fettweis from TU Dresden, talks about terahertz starting off with a look back at the history of mobile network generations up to 5G and looking ahead to 6G. Anticipating the tactile internet revolution to come, he considers the technicalities such as spectrum, channels, efficiency and adaptability needed to achieve the expected level of computing. That keynote can be viewed here.

Related Posts and articles:

Thursday, 18 July 2019

5G SpeedTests and Theoretical Max Speeds Calculations


Right now, Speed Tests are being described as 5G killer apps.



A good point by Benedict Evans



Everyone is excited and want to see how fast 5G networks can go. If you use Twitter, you will notice loads and loads of speed tests being done on 5G. An example can be seen above.


I recently heard Phil Sheppard, Director of Strategy & Architecture, '3 UK' speak about their 5G launch that is coming up soon. Phil clearly mentioned that because they have a lot more spectrum (see Operator Watch blog post here and here) in Capacity Layer, their 5G network would be faster than the other UK operators. He also provided rough real world Peak Speeds for Three and other operators as can be seen above. Of course the real world speeds greatly depend on what else is going on in the network and in the cell so this is just a guideline rather than actual advertised speeds.


I have explained multiple times that all 5G networks being rolled out today are Non-Stand Alone (NSA) 5G networks. If you don't know what SA and NSA 5G networks are, check this out. As you can see, the 5G NSA networks are actually 4G Carrier Aggregated Networks + 5G Carrier Aggregated Networks. Not all 4G spectrum will be usable in 5G networks but let's assume it is.

To calculate the theoretical maximum speed of 5G NSA networks, we can calculate the theoretical maximum 4G Network speeds + theoretical maximum 5G Network speeds.

I have looked at theoretical calculation of max LTE Carrier Aggregated Speeds here. Won't do calculation here but assuming 3CA for any network is quite possible.

I also looked at theoretical calculation of 5G FDD New Radio here but then found a website that helps with 5G NR calculation here.

If we calculate just the 5G part, looking at the picture from Three, we can see that they list BT/EE & O2 speeds as 0.61 Gbps or 610 Mbps, just for the 5G part.

Looking at the calculation, if we Input Theoretical max values in this equation:

Calculating just for DL

J - number of aggregated component carriers,
maximum number (3GPP 38.802): 16
input value: 1

v(j)Layers - maximum number of MIMO layers ,
3GPP 38.802: maximum 8 in DL, maximum 4 in UL
input value: 8

Q(j)m modulation order (3GPP 38.804)
For UL and DL Q(j)m is same (QPSK-2, 16QAM-4, 64QAM-6, 256QAM-8)
input value: 8 (256QAM)

f(j) Scaling factor (3GPP 38.306)
input value: 1

FR(j) Frequency Range 3GPP 38.104:
FR1 (450 MHz – 6000 MHz) и FR2 (24250 MHz – 52600 MHz)
input value: FR1

µ(j) -value of carrier configuration (3GPP 38.211)
For DL and UL µ(j) is same (µ(0)=15kHz, µ(1)=30kHz, µ(2)=60kHz, µ(3)=120kHz)
input value: 0 (15kHz)

BW(j)- band Bandwidth, MHz (3GPP 38.104),
should be selected with Frequency Range and µ(i) configuration:
input value: BW:40MHz FR1 µ:15kHz:

Enter a PRB value (if other)
default: 0

Rmax (if you don't know what is it, don't change)
Value depends on the type of coding from 3GPP 38.212
(For LDPC code maximum number is 948/1024 = 0.92578125)
default: 0.92578125

*** Only for TDD ***
Part of the Slots allocated for DL in TDD mode,
where 1 = 100% of Slots (3GPP 38.213, taking into account Flexible slots).
Calculated as: the number of time Slots for DL divided by 14
default value: 0.857142

Part of the Slots allocated for UL in TDD mode,
where 1 = 100% of Slots (3GPP 38.213, taking into account Flexible slots).
Calculated as: 1 minus number of Slots for DL
default value: 0.14285800000000004

Calculated 5G NR Throughput, Mbps: 1584


As you may have noticed, BTE/EE has 40 MHz spectrum while Vodafone in UK have 50 MHz of spectrum.

Changing
BW(j)- band Bandwidth, MHz (3GPP 38.104),
should be selected with Frequency Range and µ(i) configuration:
input value: BW:50MHz FR1 µ:15kHz:

Calculated 5G NR Throughput, Mbps: 1982

Now Three UK has 100 MHz, immediately available for use. So changing

µ(j) -value of carrier configuration (3GPP 38.211)
For DL and UL µ(j) is same (µ(0)=15kHz, µ(1)=30kHz, µ(2)=60kHz, µ(3)=120kHz)
input value: 1 (30kHz)

BW(j)- band Bandwidth, MHz (3GPP 38.104),
should be selected with Frequency Range and µ(i) configuration:
BW:100MHz FR1 µ:30kHz:


Calculated 5G NR Throughput, Mbps: 4006

In theory, a lot of speed is possible with the 100 MHz bandwidth that Three will be able to use. We will have to wait and see who can do a theoretical max SpeedTest. In the meantime remember that a 1Gbps speed test will use over 1 GB of data.



Related Posts:

Friday, 12 July 2019

5G and Electromagnetic energy (EME)


Every time a new generation of mobile technology is being rolled out, there are scare stories about the radiation, cancer, etc. I last wrote a post on this topic back in 2011 and also in 2009. The main thing that has changed since is that 5G is being rolled out today as 4G was being rolled out then.

The Australian operator Telstra recently completed extensive testing of their 5G network infrastructure in real-world settings using commercially available 5G devices, and their data confirms two things. Firstly, the 5G technology produces electromagnetic energy (EME) levels at around 1000 times below the safety limits in many cases. Secondly, all the testing has found 5G EME levels to be similar to 3G, 4G and Wi-Fi. You can read the details and complete report here.

Last month I went to a seminar titled 'Update on Current Knowledge of RF Safety', organised by CW Radio Technology Group and National Register of RF Workers. Richard Hargrave from BT explained the challenge with compliance when a 5G carrier is added.

The implications as he said are:
  • Some sites in urban areas become increasingly difficult to provide required capacity while maintaining compliance using standard designs
  • Significant time and cost can be associated with works necessary to ensure compliance – new planning permissions, physical structures, new site acquisition etc
  • As 5G is deployed further, particularly as additional spectrum is auctioned in 700MHz and 3.6-3.8GHz bands these problems will be exacerbated

His presentation is available here. Another presentation from Moray Rumney, asking some tough question on 5G safety is available here. Simon Rockman has written a summary of this seminar on Forbes, here.

I heard the Swiss operator Sunrise mentioning in a presentation at 5G World 2019 that the EMF limit in Switzerland is 10 times stricter than the rest of the world. This implies that 5G in Switzerland is extremely safe. The slide from the presentation can be seen in the pic above.

We also have couple of related videos on this topic, maybe of interest:

Further Reading:

Tuesday, 9 July 2019

3GPP 5G Standardization Update post RAN#84 (July 2019)

3GPP recently conducted a webinar with Balazs Bertenyi, Chairman of 3GPP RAN in which he goes through some of the key features for 5G Phase 2. The webinar also goes through the details of 5G Release-15 completion, status of Release-16 and a preview of some of Release-17 features.

Slides & video embedded below. Slides can be downloaded from 3GPP website here.







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Saturday, 6 July 2019