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Future Wireless Communication Protocols in Autonomous Systems

What are Autonomous Systems (AS)? Why do they need to be connected? Why do automotive manufacturers care so much about 5G NR C-V2X and 802.11bd? What are communication tendencies in AS? A light will be shed on these questions in this blog.

Introduction – What are autonomous systems?

This term consists of two words. The first “Autonomous” means self-governing, i.e. without human intervention. The second “Systems” stands for a set of complicated parts forming together a complex and intelligent whole. When we connect these two words we get something complex, comprising an independently operating system capable to learn, adapt and scan the environment. In the near future, these AS will be deployed throughout the world and they will take over important tasks in different sectors such as:

  • Automotive;
  • Marine;
  • Aerial;
  • Agricultural;
  • Medical.

AS will also be intelligent and complex in terms of communication. One of their features is connectivity which stands for pairing autonomous systems between each other as well as with non-AS objects and systems. What does connectivity bring? First of all and the most important is safety, and only secondly, it’s the user’s convenience. For instance, in the automotive sector, there is a strict division between safety and non-safety applications which can be realized using V2X (vehicle to everything) communication to provide each other with information about obstacles, pedestrians, next manoeuvres, etc. In the agricultural sector tractor platooning can be realized allowing a number of tractors to move simultaneously in the same pattern.

In this blog, we will discuss the wireless communication protocols that are likely to be used in AS. Their planned or possible implementations and functions will be highlighted as well.

Automotive Sector

AS in the automotive sector are currently one of the most advanced and are being developed with great strides. Intelligent Transportation Systems or ITS (this is how AS are called in this sector) will be primarily designed to optimize traffic and to increase road safety.

For ITS applications (safety and non-safety) in the European countries a dedicated BandWidth (BW) of 70MHz between 5855 and 5925MHz is divided into seven channels (10MHz each one).

Communication can be realized using two main wireless technologies:

  • Wi-Fi (regulated by the European standard ETSI EN 302 663 V1.3.1 mostly referred to as “ITS-G5” based on the US IEEE 802.11p standard which was incorporated into IEEE 802.11-2012 and later into the IEEE 802.11-2016 and now is updating and will get the name IEEE 802.11bd. For convenience in this blog an original old name IEEE 802.11p or shortly “802.11p” will be used;

  • Cellular 4G and 5G standardized by 3GPP and issued under ETSI standards (ETSI TR 121 915 V15.0.0 mostly referred to as “3GPP release 15” or “5G NR C-V2X” what stands for 5G New Radio communication introduced in V2X applications). For the convenience and simplicity 4G and 5G will be used.

Depending on the communication means of realization (cellular or wireless local area network or WLAN or WiFi) one may define “workgroups” closely collaborating with each other. Schematic hierarchy can be roughly presented as shown in Fig.1, where arrows represent assumed and simplified dependency and hierarchical contribution to standards development. As one may find from Fig. 1, a lot of companies are involved in cars of the future and the technology used and applied in this sector is not yet fully standardised by the European Union.

Figure 1. Main contributors to ITS standards development in Europe

With the help of the aforementioned protocols, one may establish communications named as V2X which comprises safety and non-safety applications differing in functions and purposes (shown in Fig. 2).

Figure 2. V2X implementations. Courtesy of Qualcomm.

All of these communications can be established either using WLAN or cellular network apart from Vehicle-to-Network which can be done only via a cellular network. However, protocol design and its performance differs from what is shown on slides from Qualcomm [1].

ETSI prescribes a number of parameters to AS. One of them is the allowed maximum latency (the maximum duration of time allowable between when information is available to be transmitted and when it is received), which should be less than 50 ms for critical functionalities (e.g. a pre-crash sensing warning) while for other applications it can be up to 200 ms (for traffic efficiency) and even 500 ms (for non-safety infotainment applications). As for data rates, in the 5G Automotive Vision report [2], it was envisioned that Vehicle-to-Vehicle connection can demand up to 20 Mbits/s data rate to be transmitted from one device to another in 10 ms.

Marine Sector

Besides safety issues (like it is done in the automotive sector), autonomous vessels also focus on optimizing fuel consumption when travelling from the embarkment point to the destination point.

The marine sector has already started to use 3GPP to implement terrestrial technologies and one has prepared requirements for marine communication services as outlined in [3]. Alternatives and tendencies in the marine sector were discussed and offered in [4]. In the same paper, the communication architecture of an autonomous ship was presented (Fig. 3) where one may notice several wireless communication systems and technologies to be considered: HAP (high altitude platforms), satellite systems, WiFi (802.11 and 802.11p) and 4G/5G.

Figure 3. The communication architecture of an autonomous ship. Courtesy of [4].

The abovementioned types of communication will be used both for ship-to-ship connections and for ship-to-the-remote-shore-control-centre connection. There was also a proposal to transmit information first to the other ships situated at a certain point of time closer to the shore control centre. This concept is named a “ship mega-constellation” which enables to create a mobile ad-hoc network with multi-hop features.

In the project called “Roboat” carried out by the Massachusetts Institute of Technology and the Amsterdam Institute for Advanced Metropolitan Solutions, WiFi is used to perform control actions from the captain Roboat to any other Roboat in a swarm [5].

Aerial Sector

In this sector, there are two main categories of flying autonomous vehicles:

  • airplanes (urban taxis and long-distance airplanes)
  • drones or unmanned aerial vehicles (UAV).

These devices have a long path to the broad market and everyday life but there has already been performed a lot of research work and tests with UAVs. Prof. C. Bettstetter (The University of Klagenfurt, Austria) explained UAVs’ possible communication means in multi-drone systems (or drone-to-drone communication) on his website [6]. According to Prof. Bettstetter, UAVs may use IEEE 802.11 protocols but with preliminary modified antennas in order to achieve quasi-isotropic radiation providing uniform 3D-connectivity [7], as, without this measure, these protocols provide poor communication. Another means of connecting UAVs is cellular communication, i.e. 4G and 5G. These protocols have their own disadvantages, for instance, proneness to interferences possibly because of certain behaviour in cell selection in the aerial volume [8]. Nonetheless, according to Ericsson’s team [9], 4G/5G is a promising wireless communication means enabling not only drones-to-drones connectivity but also aiding to track, identify UAVs and detect uncertified use of mobile devices (because they cause unintentional interferences) in UAVs.

The application of UAVs differs. Apart from military usage, a UAV can serve as a first-hand information gathering and streaming tool during emergency cases (e.g. “The safety Drone” by Citymesh) or as a package deliverer like Amazon’s “Prime Air”.

VVA (a consultancy company) has made a cost assessment model for different types of drone usage [10] (see Fig. 4). Now imagine a swarm of connected drones using a wireless technology delivering multiple medical packages to their recipients. In a large scale it can save lots of people’s life because the time is crucial when it comes to health.

Figure 4. Drones biomedical samples delivery efficiency. Courtesy of VVA.

Agricultural Sector

Modern tractors are equipped with all the necessary modules: Bluetooth, cellular connection (4G) and Wi-Fi and some people define such tractors as IoTs.

One may notice two main tendencies for connectivity of an agricultural vehicle (AgV). On the one hand, cloud-connection, i.e. uploading the current data: location, speed, working status, fuel tank level to the cloud from one AgV and then downloading it by another AgV or by a supervisor). On the other hand, tractor-to-tractor direct connection or M2M (machine-to-machine). Using Wi-Fi or IEEE 802.15.4 variations (e.g. 6LoWPAN which transmits at a frequency of 2.4 GHz with a maximum speed of 250 kbps and a latency of 100 ms [11]) the M2M connection can be established and using 4G – the cloud-connection can be guaranteed. As for the usage of 4G in the cloud-connection, its main disadvantage is quite a high transmission time: to get the needed information from the AgV1 to the cloud then downloading and processing it by the AgV2 one may need times ranging from 30 to 60 seconds. Meanwhile, the promising technology of 5G with the help of “Industry 4.0” and projects like 5GACIA could solve this issue and diminish this time to 1 second.

Finally, ETSI is planning [12] to connect AgVs with road vehicles (cars, motorcycles, etc.) to reduce accidents involving AgVs by warning drivers about AgVs on the road. One may consider an AgV as a vehicle what is true by definition but in reality differs because of completely different (non)safety applications.

AS in the agricultural sector will help to decrease fuel consumption, accidents and improve the efficiency of farming not only implementing very precise sowing and burrowing systems but also making a 24/24 and 7/7 working scheme possible.

Medical Sector

This sector is less represented than others. There are several projects (Da Vinci surgical system [13] and smart autonomous robotic assistant surgeon [14]). However, Da Vinci’s system is quite mature and has already been fully deployed. It uses a wireless bridge for system information exchange for faults diagnosis and getting updates for Da Vinci’s system enabling or disabling features. The system’s wireless connectivity works on the standards 802.11b, g and n with a requirement of no more than 20% utilization of the dedicated channel and latency of 50 ms between the access point and the Da Vinci’s wireless module [15].

Autonomous surgical systems will assist current surgeons by making precise incisions and suturing.

Summary

All the information above can be represented in Table I depicting for each of the discussed sectors where AS will appear and possible means of wireless communication for different applications.

Albeit AS are not fully ready in every sector, they will definitely conquer the market in the near future and will aid people to perform their tasks with more efficiency and safety. The last step to be made from mankind is to establish sufficient trust in these novelties.

References

[1] Qualcomm, “Accelerating C-V2X commercialization,” 2017.

[2] The 5G Infrastructure Public Private Partnership, “5G Automotive Vision,” 5G-PPP Initiat., pp. 1–67, 2015.

[3] 3GPP, “3GPP TS 22.119 V16.1.0 (2019-09) 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Maritime Communication Services over 3GPP system; Stage 1 (Release 16).” 2019.

[4] M. Hoyhtya, J. Huusko, M. Kiviranta, K. Solberg, and J. Rokka, “Connectivity for autonomous ships: Architecture, use cases, and research challenges,” Int. Conf. Inf. Commun. Technol. Converg. ICT Converg. Technol. Lead. Fourth Ind. Revolution, ICTC 2017, vol. 2017-Decem, no. October, pp. 345–350, 2017, doi: 10.1109/ICTC.2017.8191000.

[5] D. Scimeca, “Waterborne drone swarms use 3D cameras to communicate AprilTag markers and depth cameras enable intelligence on reconfigurable roboats.,” 2019. [Online]. Available: https://www.vision-systems.com/non-factory/scientific-industrial-research/article/14068730/roboat-drone-swarms-from-massachusetts-institute-of-technology-use-apriltags-and-3d-cameras-to-communicate. [Accessed: 13-Mar-2020].

[6] C. Bettstetter, “Communications and Path Planning of Drones.” [Online]. Available: https://bettstetter.com/research/uav/. [Accessed: 13-Mar-2020].

[7] E. Yanmaz, R. Kuschnig, and C. Bettstetter, “Achieving air-ground communications in 802.11 networks with three-dimensional aerial mobility,” Proc. – IEEE INFOCOM, pp. 120–124, 2013, doi: 10.1109/INFCOM.2013.6566747.

[8] S. Hayat, C. Bettstetter, A. Fakhreddine, R. Muzaffar, and D. Emini, “Handover challenges for cellular-connected drones,” DroNet 2019 – Proc. 5th Work. Micro Aer. Veh. Networks, Syst. Appl. co-located with MobiSys 2019, pp. 9–14, 2019, doi: 10.1145/3325421.3329770.

[9] “Drones & networks: safe & secure|Whitepaper – Ericsson.” [Online]. Available: https://www.ericsson.com/en/reports-and-papers/white-papers/drones-and-networks-ensuring-safe-and-secure-operations. [Accessed: 13-Mar-2020].

[10] T. Tavares, “Comparing the cost-effectiveness of drones v ground vehicles for medical, food and parcel deliveries – Unmanned airspace.” [Online]. Available: https://www.unmannedairspace.info/commentary/comparing-the-cost-effectiveness-of-drones-v-ground-vehicles-for-medical-food-and-parcel-deliveries/. [Accessed: 16-Mar-2020].

[11] X. Zhang, M. Geimer, P. O. Noack, and L. Grandi, “Development of an intelligent master-slave system between agricultural vehicles,” IEEE Intell. Veh. Symp. Proc., no. September 2014, pp. 250–255, 2010, doi: 10.1109/IVS.2010.5548056.

[12] S. Antipolis, “ETSI sets a worldwide first with a tractor that communicates with cars,” 2018. [Online]. Available: https://www.etsi.org/committee?id=1385. [Accessed: 13-Mar-2020].

[13] “Intuitive | Robotic Assisted Systems | da Vinci Robot.” [Online]. Available: https://www.intuitive.com/en-us/products-and-services/da-vinci/systems. [Accessed: 16-Mar-2020].

[14] “SARAS-Project – Saras Project.” [Online]. Available: https://saras-project.eu/. [Accessed: 16-Mar-2020].

[15] “OnSite TM for the da Vinci ® Surgical System Overview,” pp. 1–12.

 

About the Author: Aleksandr Ovechkin


Aleksandr graduated from NRU “MPEI” (Russia) with a Master’s degree which was dedicated to investigating the work of battery chargers during short circuits on the DC distribution systems. Later he joined the structural design engineering team and worked there in the electrical engineering department. While working in a company, Aleksandr didn’t quit research activity and he decided, after getting useful work experience, to completely focus on his research as a PhD student.