PETAR POPOVSKI AALBORG UNIVERSITY - CHALLENGES AND POSSIBILITIES FOR WIRELESS IOT - WILAB
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challenges and possibilities for wireless IoT connectivity on the path beyond 5G Petar Popovski Aalborg University Denmark petarp@es.aau.dk WiLab - Huawei JIC Workshop, January 11, 2021
outline connectivity types IoT and time IoT and space transforming the IoT traffic WiLab - Huawei JIC Workshop, January 11, 2021 2
outline connectivity types IoT and time IoT and space transforming the IoT traffic WiLab - Huawei JIC Workshop, January 11, 2021 3
the complex connectivity ecosystem Video server internet Logistics data WiLab - Huawei JIC Workshop, January 11, 2021 4
how 5G deals with this complexity enhanced Mobile Broadband Ultra-Reliable Low Latency Communication massive Machine Type Communication perhaps the main innovation in 5G: offer a platform for flexible support of heterogeneous services WiLab - Huawei JIC Workshop, January 11, 2021 5
the space of connectivity services URLLC mMTC IA: Industrial Automation V2V-3 IA-1 VR: Virtual Reality VR-2 VR-1 V2V: Vehicle-to-Vehicle eMBB WiLab - Huawei JIC Workshop, January 11, 2021 6
decoupling reliability from low latency resilient connections with large latency budget disaster and rescue mobile health, remote monitoring smart grid this decoupling is visible in the new 5G requirements posed by 3GPP (Sep 2020) WiLab - Huawei JIC Workshop, January 11, 2021 7
connectivity space revisited reliability data rate tactile robotics health monitors augmented reality latency massiveness WiLab - Huawei JIC Workshop, January 11, 2021 8
the traffic model challenge need for improved understanding of the connection ecosystem population of connections generic reliability latency connectivity data rate massiveness types characterization of the composite connections § example: low latency traffic arrivals from the same device correlated with broadband requests time WiLab - Huawei JIC Workshop, January 11, 2021 9
simultaneous massive and ultra-reliable? mMTC URLLC possible when the information across devices is correlated (e.g. alarm) WiLab - Huawei JIC Workshop, January 11, 2021 10
illustrative scenario that cobines mMTC and URLLC ps pd pd ps Physical pd ps Phenomenon pd ps pd ps g. 1. System model with common alarm and standard messages. pd denotes the probability of detecting an alarm, and ps is the probability of send andard message. a device generates two message types recludes the identification of users and the error measure is done on a per-device basis. This has also been called unsou § individual update, independent of others andom access [11]. § we In this alarm-type message, build upon the model correlated in [1] with an forweallbring important extension: sensors in the correlation of activation and mes ontent across different devices. This is different from the mainstream view on massive random access, where the de ctivation K.and message Stern, A. content is independent E. Kalør, B. Soret,across andtheP.devices. An exemplary Popovski, case is "Massive as follows:Access Random IoT devices can s andardwith Common messages or alarm Alarm Messages", messages, the latter with in Proc. critical IEEErequirement reliability ISIT, Paris, France,byJuly and triggered 2019. obse a commonly henomenon. In normal operation, standard uncorrelated messages are sent. Upon the alarm activation, a number of evices will prioritize it and send WiLab - Huawei the same JICThis message. Workshop, reflectsJanuary 11, 2021 the extreme all-or-nothing correlation where11devices
heterogeneity brings a new dimension to spectrum usage the first topic listed in EU Commission call for projects 5G PPP – Smart Connectivity beyond 5G “Provision of seemingly infinite network capacity including innovative spectrum use and management …” Basil but how do we measure the spectrum capacity when one user wants a high rate Zoya Yoshi and another one wants a fixed rate, broadband low-latency low latency and high reliability? connectivity critical connectivity WiLab - Huawei JIC Workshop, January 11, 2021 12
heterogeneity brings a new dimension to spectrum usage eMBB data rate mMTC arrivals slicing in spectrum domain • orthogonal • non-orthogonal WiLab - Huawei JIC Workshop, January 11, 2021 13
outline connectivity types IoT and time IoT and space transforming the IoT traffic WiLab - Huawei JIC Workshop, January 11, 2021 14
latency-reliability characterization fixed data size reliability=Pr( ≤ ) 1 1-Pe latency t WiLab - Huawei JIC Workshop, January 11, 2021
design targets broadband rate-oriented ultra-reliable low latency systems communication URLLC reliability reliability 1 1 latency latency WiLab - Huawei JIC Workshop, January 11, 2021
timing requirements Fig. 4: Relationship beyond between application device and latency communication device (3GPP TS 22.104 [2]). AF = Application function (source and target) HCL = Higher communication layer Source: 3GPP TS 22.104 [2] OS = Operating system (source and target) LCL = Lower communication layer Relationship between application device and communication device [3] In control applications, transmissions of data and control commands often have to be com- [3] 3GPP Technical pleted Specification within a given 22.104. “Service time period. requirements This time for cyber-physical period determines control the maximum applications in permissible vertical domains” https://www.3gpp.org/ftp/Specs/archive/22_series/22.104/ end-to-end latency. WiLab - Huawei JIC Workshop, January 11, 2021 5.4 Diagnostics
latency vs. age § latency performance historically characterized with packet delays § other timing requirements – tracking applications and sense-compute-actuate cycles are not sensitive to packet delay, but to the freshness of the information at the receiver example: satellite-based tracking WiLab - Huawei JIC Workshop, January 11, 2021 18
Age of Information § Age of Information (AoI) and its byproducts are better metrics to capture the freshness of the information § exogeneous vs. controlled sampling (generate-at-will) AoI ... t1 t2 t3 t4 time tִ 1 tִ 2 tִ 3 tִ 4 inter-arrival time system t ime [1] S. Kaul, R. Yates, and M. Gruteser, “Real-time status: How often should one update?” in International Conference on Computer Communications. IEEE, Mar. 2012, pp. 2731–2735. [2] A. Kosta, N. Pappas, and V. Angelakis. "Age of information: A new concept, metric, and tool." Foundations and Trends in Networking 12.3 (2017): 162-259. WiLab - Huawei JIC Workshop, January 11, 2021 19
Peak Age of Information (PAoI) § Peak Age of Information (AoI) measures how old the last packet is when the new one arrives at the destination AoI PAoI1 PAoI2 ... t1 t2 t3 t4 time tִ 1 tִ 2 tִ 3 tִ 4 inter-arrival time system t ime M. Costa, M. Codreanu, and A. Ephremides, “Age of information with packet management,” in 2014 IEEE International Symposium on Information Theory, pp. 1583–1587, June 2014. WiLab - Huawei JIC Workshop, January 11, 2021 20
case study: PAoI in edge computing 3 model with a tandem queue µ1 µ2 4 Fig. 1: An example of the IoT edge computing use case: the sensor transmits data to a computing-enabled edge node, which needs to maintain information freshness. AoI PAoI 1 PAoI 3 representing the model in the edge computing scenario: bothPAoI the2 transmission and the PAoI edge 4 PAoI n computation can be buffered, and the system is a tandem queue. If the load on the computing-enabled edge node is time constant, while communication is Aoi less predictable due to, e.g., dynamic channel variations and random access, then the M/M/1 end node – M/D/1 tandem queue is an appropriate model. Computation time is often modeled as a linear function of the data size in the literature [7], and updates of the same size would have a intermediate constant and deterministic service time. Modeling the channel as an M/M/1 queue is correct if we assume an ALOHA system [8] with perfect Multi-Packet Reception (MPR), in which // gn 1[9]gn g1 g2 g3 g4 the packets are not lost due to collisions and can only be lost due to channel errors. This model time F. Chiariotti, O. Vikhrova, B. Soret, and P. Popovski. t "Peak Age of Information Distribution in is suitable for IoT systems based on Ultra-Narrowband (UNB) transmissions, such as SigFox Tandem Queue Systems." Fig. 2: arXiv Change the y-axis frompreprint arXiv:2004.05088 Aoi to AoIThe time-evolution of the Age (2020). [10]. Another option is to consider the computing load as also variable over time, leading to of Information in a 2-node tandem queue. The age at the destination is plotted in black, the age at the intermediate node is plotted in red. Departures from stochastic computing time, and represent the two systems by M/M/1 queues with different each node are marked by a circle. WiLab - Huawei JIC Workshop, January 11, 2021 21 service rates [11].
study of the distribution of PAoI derived the PAoI pdf for § M/M/1 and M/D/1 tandem queue (constant computation time) § M/M/1 and M/M/1 tandem queue (two independent satellite links) 9 µ1 µ2 Transmission buffer Communication link Edge node queue Computing gi 1 ⌦i 1,1 Yi,1 gi Si 1,1 ⌦i,1 Time ⌦i i 1,2 Si,1 Si 1,1 ri ⌦i,2 Si,1 ri 1 Fig. 3: Schematic of the four steps a packet goes through in a tandem queue, highlighting the components of the F.PAoI. Chiariotti, O. Vikhrova, B. Soret, and P. Popovski. "Peak Age of Information Distribution in Tandem Queue Systems." arXiv preprint arXiv:2004.05088 (2020). The reason we named ⌦WiLab i,j the- extended waiting Huawei JIC time is Workshop, that W11, January i,j = [⌦i,j ]+ , where [x]+ is equal 2021 22
Age of Incorrect Information (AAoI) 92 5.3. System Overview Chapter 5. Age of Incorrect Information: Analysis and Optimization (a) Age penalty function. (b) Error penalty function. Figure 5.3: Illustration of the proposed penalty function. age penalty Figure functionof the age and error 5.2: Illustrations errorpenalty penalty function functions. combined penalty function 5.3 System Overview 5.3.1 System Model error penalty function is its failure to capture the following phenomena that arises in numerous applications: staying in an erroneous state should have an Inincreasing this chapter, we consider a transmitter-receiver pair where the transmitter s status updates about the process of interest to the receiver side over an unrel penalty effect. In fact, the function in (5.2) treats all instances of error equally, no channel. Time is considered to be slotted and normalized to the slot duration matter how long the time elapsed since their start is. In other words, the penalty the slot duration is taken as 1). The information process of interest is an N s A.of being in an erroneous state after 1 time slot or 100 time slots is the same Maatouk, S. Kriouile, M. Assaad, and A. Ephremides, discrete 1. Because of this observation, we can see that the long-time average error “The value age of Markov penalty incorrect chain information: X(t) t2N depicted A that in Fig. 5.4. To new extent, we defin probability of remaining at the same state in the next time echelon as Pr(X(t + performance metric due to a burst error is thefor samestatus updates,” as the one IEEE/ACM resulting from Transactions several isolated errors X(t)) = pRof on Networking, . Similarly, the probability ofpp. 1–14,to2020. transitioning another state is define Pr(X(t the same duration. However, this is not always the case. There is a vast amount of + 1) 6 = X(t)) = p t . Since the process in question can have one of N diffe possible applications where the penalty grows the longer the monitor has incorrect informa- values, the following always holds: tion. For example, let us suppose that X(t) = 1 refers to the case where a machine pR + (N 1)pt = 1. (5 is at a normal temperature at time WiLabt and- X(t) = 2 isJIC Huawei the case where the January Workshop, machine is11, 2021 23 overheating. This information has to be transferred to a monitor that can,Asconse- for the unreliable channel model, we suppose that the channel realiza
+ Department of Computer Science, Aalborg University Query Process AoI in pull-based communication Selma Lagerløfs Vej 300, 9220 Aalborg, Denmark, email: {skj,tbp}@cs.aau.dk tti ∗ , Beatriz stract—Age Soret∗ , Søren of Information (AoI) has Jensenan+,important K. become Q1 Q2 Q3 common §freshness pt in communications, etarthePopovski ure ∗ ascommunication models are push-based it allows system designers of the information available to remote to , Aalborg toring med § or pull-based University control communication: processes. However, its definition tacitly that new information is used at any time, which is not 1 2 3 4 5 6 7 il: {jho,aek,fchi,bsa,petarp}@es.aau.dk ys the casereading process and the instants at whichthat is different information is collectedfrom permanent subscription (a) Permanent query transmissions , Aalborg used University are dependent on a certain query process. We propose Q1 Q2 Q3 del that mark, – satellites, cloud-based {skj,tbp}@cs.aau.dk accounts email: queries for the discrete time nature of many to the edge devices, data fetching in a control loop toring processes, considering a pull-based communication 1 2 3 4 5 6 l in which the freshness of information is only important the receiver generates a query. We then define the Age (b) Query-aware transmissions formation at Q1Query (QAoI), a Q2 more general metricQ3 that Permanent query he pull-based scenario, and show how its optimization can Query-aware to very different choices from traditional push-based AoI mization when 1 using 2 a Packet 3 Erasure 4 Channel 5 6(PEC). 7 dex Terms—Age of Information, networked control systems AoI (a) Permanent query transmissions Q1 Q2 Q3 I. I NTRODUCTION ver the past 1 2 few years, the concept 3 4 of information5 6fresh- has received a significant attention in relation to cyber- ical systems that (b) rely Query-aware transmissions on communication of various up-time Q1 Q2 Q3 time in real time. This has led to the introduction Permanent query of Age of t mation (AoI) [1] as a measure that reflects the freshness Query-aware (c) Age for the two systems e receiver J. Holm,with A. E. respect to the sender, Kalør, F. Chiariotti, andS.denotes B. Soret, theT. B. Pedersen, and P. Popovski. "Freshness on Demand: Optimizing K. Jensen, renceAge between the current time andProcess." the timearXiv when Fig. 1: Example of the difference between a system assuming the arXiv:2011.00917 of Information for the Query preprint a permanent query (2020). and one that is aware of the query arrival AoI recently received update was generated at the sender. e first works to deal with AoI considered simple queuing process. The same packets are lost (depicted in red) in both ms, deriving analytical formulas WiLab - Huawei fresh- for information JIC Workshop, systems,January and the 11, 2021 indicate the age at the query24arrival markers instants.
outline connectivity types IoT and time IoT and space transforming the IoT traffic WiLab - Huawei JIC Workshop, January 11, 2021 25
systems with massive number of antennas 1 § massive MIMO Massive MIMO for Internet of Things (IoT) Connectivity § Large Intelligent Surfaces Alexandru-Sabin Bana1 , Elisabeth de Carvalho1 , Beatriz Soret1 , Taufik Abrão2 , José Carlos Marinello2 , Erik G. Larsson3 , and Petar Popovski1 1 Department of Electronic Systems, Aalborg University, Denmark § Reconfigurable Intelligent Surfaces New generation of access points: 3 • Low cost, low weight, easy to deploy electromagnetic panels 2 Electrical Engineering Department, Londrina State University, Parana, Brazil Department of Electrical Engineering (ISY), Linköping University, 581 83 Linköping, Sweden • Easily integrable in the surroundings • Access points closer to the users Abstract—Massive MIMO is considered to be one of the key tech- nologies in the emerging 5G systems, but also a concept applicable to other wireless systems. Exploiting the large number of degrees of freedom 905.06205v1 [cs.IT] 15 May 2019 (DoFs) of massive MIMO essential for achieving high spectral efficiency, high data rates and extreme spatial multiplexing of densely distributed users. On the one hand, the benefits of applying massive MIMO for short packets broadband communication are well known and there has been a large body of research on designing communication schemes to support high rates. On the other hand, using massive MIMO for Internet-of-Things low latency (IoT) is still a developing topic, as IoT connectivity has requirements eMBB VR URLLC and constraints that are significantly different from the broadband high data rate connections. In this paper we investigate the applicability of massive high reliability MIMO to IoT connectivity. Specifically, we treat the two generic types of IoT connections envisioned in 5G: massive machine-type communication (mMTC) and ultra-reliable low-latency communication (URLLC). This paper fills this important gap by identifying the opportunities and mMTC challenges in exploiting massive MIMO for IoT connectivity. We provide insights into the trade-offs that emerge when massive MIMO is applied to mMTC or URLLC and present a number of suitable communication numerous schemes. The discussion continues to the questions of network slicing of devices short packets the wireless resources and the use of massive MIMO to simultaneously support IoT connections with very heterogeneous requirements. The main sporadic traffic conclusion is that massive MIMO can bring benefits to the scenarios with IoT connectivity, but it requires tight integration of the physical-layer Figure 1. Massive MIMO and the 5G services. techniques with the protocol design. Index Terms—mMTC; URLLC; Massive MIMO; 5G; Activity de- The other two services, URLLC and mMTC, are the cornerstones tection; Collision resolution; Extended coverage; short packets; NR; Random Access (RA); Grant-based RA; Grant-free RA; Unsourced of machine-type traffic and thus enablers of various types of Internet RA; Network Slicing; compressing sensing; sparsification; covariance of Things (IoT) connectivity. URLLC, also known as mission-critical methods; Cross-layer optimization design IoT, envisions transmission of moderately small data packets (in WiLab - Huawei JIC Workshop, the order January 11, of2021 tens of bytes) with extremely high-reliability, ranging 26 between 99.999% and 99.9999999%, i.e. down to 10 9 packet I. I NTRODUCTION error probability [1]. The user plane latency requirement is most
massive MIMO and IoT pros § very high SNR links § quasi-deterministic links, fading immunity § extreme spatial multiplexing capability cons § expensive CSI acquisition procedure § additional protocol steps WiLab - Huawei JIC Workshop, January 11, 2021 27
massive MIMO and IoT 9 M ULTI -A NTENNA S YSTEMS VE factory scenario with predefined Multi-Antenna spatial Systems for URLLC he base station orchannels terminals of a fficient mechanisms at the physical low latency communications. They ent to the higher layer methods de- section focuses on massive antenna a very large number of antennas at terminals, at high frequency bands, d as a major enabler towards the works [37]. They are largely viewed g the data rates and/or increasing users that can be simultaneously me bandwidth. However, they are building the two other 5G services, Fig. 6. Factory scenario where a massive MIMO access points serves multiple communications [38] and URLLC terminals (workstations). A.-S. Bana, E. de Carvalho, B. Soret, T. Abrao, J. C. Marinello, E. G. Larsson, P. Popovski, “Massive antenna MIMO lie systems for in Internet of Things (IoT) Connectivity”, https://arxiv.org/abs/1905.06205 their ability mber of spatial Degrees-of-Freedom B. Channel Structure he following remarkable properties To illustrate the main concepts of this section, we assume a WiLab - Huawei JIC Workshop, January 11, 2021 28 LLC: factory-type environment as pictured in Fig. 6. An access point
Collection of closely spaced tiny antenna elements over a large surface simple IoT devices and Reconfigurable Intelligent Surfaces Provides a high resolution image of the propagation environment RIS Base Station 14 simple IoT devices can benefit significantly from the favorable and reconfigurable wireless environment WiLab - Huawei JIC Workshop, January 11, 2021 29
Sensing case study: RIS helps satellite IoT Collection of closely spaced tiny antenna elements over a large surface Provides a high resolution image of the propagation environment 5 Isotropic IRS Planar IRS, 45° tilt Diffuse Reflector 10° 25° 50° 90° 50° 25° 10° Without IRS Planar IRS, 0° tilt Specular Reflector 8 IRS Gain [dB] 10° 25° 50° 90° 50° 25° 10° 6 Channel Gain [dB] 155 4 160 2 0 165 400 200 0 200 400 170 Time [s] & Elevation Angle (top) 400 200 0 200 400 Fig. 4. Gain of using IRS over LOS only communication (legend as in Fig. 3). Time [s] & Elevation Angle (top) shown that the phase shifts can be chosen such that they Fig. 3. Channel gain over time for one satellite pass. The plots of the scenarios 14 incurring any Doppler without IRS and with reflectors are congruent. maximize the received power without spread. Moreover, they can be kept within the interval [0, 2⇡] and as a diffuse reflector with phase shifts chosen by Snell’s which is in the feasible range of recent IRS prototypes [7]. It § predictive satellite mobility used to adjust the reflective surface law and uniformly in the interval [0, 2⇡], respectively. These configurations emulate the behavior of a planar obstacle that also results in the minimum delay spread under meaningful IRS operation. In a numerical study, we demonstrate the benefits reflects the signal in place of the IRS. Further, to obtain an of IRS-assisted LEO satellite communication and show that § multi-objective optimization: upper bound that serves as a best case deployment, we consider the SNR is increased by 3 dB to 6 dB for an IRS the size of an IRS with isotropic elements, i.e., G(✓, ') = 1 for ✓ 2 [0, ⇡2 ] two billboards. This requires rotating the IRS such that it has received power, Doppler spread and delay spread and zero otherwise. The number of elements in this case is a favorable orientation to the transmitter and receiver. Finding chosen such that the effective antenna area matches the size of this optimal orientation is left open for future work. Other 2 the IRS. With an effective area per element of 4⇡ this amounts open topics are the inclusion of statistical channel model to to 433 ⇥ 288 elements. account for atmospheric effects and LOS outages. B. Matthiesen, E. Björnson, E. De Carvalho and P. Popovski, "Intelligent Reflecting Surface It can be observed from Fig. 3 that the gain of the IRS R EFERENCES Operation under Predictable Receiver Mobility: A Continuous Time Propagation Model," in IEEE with isotropic elements over the baseline is 7.9 dB. This is also directly displayed in Fig. 4. In contrast, the gain of the [1] C. Liaskos et al., “A new wireless communication paradigm through Wireless Communications Letters, 2020. IRS with planar elements is negligible. This is due to the software-controlled metasurfaces,” IEEE Commun. Mag., vol. 56, no. 9, pp. 162–169, Sep. 2018. unfavorable angle of the receiver towards the IRS which reduces [2] M. Di Renzo et al., “Smart radio environments empowered by recon- the effective area of the IRS to nearly zero. This issue can figurable AI meta-surfaces: an idea whose time has come,” EURASIP J. WiLab be avoided- by Huawei physicallyJIC Workshop, rotating the IRS towardsJanuary the sky. In11, 2021 Wireless Commun. Netw., vol. 2019, no. 1, May 2019. 30 [3] E. Basar et al., “Wireless communications through reconfigurable particular, by rotating the x-axis by 45° and keeping the IRS intelligent surfaces,” IEEE Access, vol. 7, pp. 116 753–116 773, 2019.
massive satellite IoT aided by RIS Sensing Collection of closely spaced tiny antenna elements over a larg sely spaced tiny antenna elements over a large surface Provides a high resolution image of the propagation enviro resolution image of the propagation environment 14 WiLab - Huawei JIC Workshop, January 11, 2021 31
outline connectivity types IoT and time IoT and space transforming the IoT traffic WiLab - Huawei JIC Workshop, January 11, 2021 32
interactions in massive IoT systems how interactions in massive IoT systems were envisioned: • mostly uplink transmissions • assumption reflected in a lot of mainstream mMTC systems, such as LoRa and SigFox at least two drivers to change the patterns of interaction • smart contracts and blockchains • distributed learning WiLab - Huawei JIC Workshop, January 11, 2021 33
smart contract mple Use Case II: Transportation Rental § a digital contract that combines The smart The smart Jane uses a – programmed computer Upon deposit, the smart Janefunctions returns contract monitors bike to a contract transfers funds mart contract contract different rental speed and to RentCo and – logic for legal documents o rent a ride. unlocks bike for use. point. distance with relocks the ride tracking. bike. § example (from labCFTC) Smart RentCo RTS Smart Contract Running Tracks and transfers fees, fines, payments and refunds. Alerts RentCo if Jane Ride Tracking strays outside of service area. Locks/unlocks ride. Service Jane Oracle tracks location, speed, and accidents. Jane can see records of her rides on the Smart Contract Blockchain. 14 LabCFTC, A Primer on Smart Contracts, https://www.cftc.gov/sites/default/files/2018- 11/LabCFTC_PrimerSmartContracts112718.pdf WiLab - Huawei JIC Workshop, January 11, 2021
IoT and smart contracts IoT smart contracts distributed IoT IoT decentralized apps ledger connectivity connectivity security § massive amount of transactions and contracts among autonomous connected devices WiLab - Huawei JIC Workshop, January 11, 2021 35
example: pollution monitoring with IoT and blockchain Marketplace Connectivity Distributed Distributed Trust Transparency Blockchain Pollution Tamper-Proof Smart Contract Monitoring Sensing Data Analytics Connectivity Sensing Data Analytic Micro-Transactions Marketplace WiLab - Huawei JIC Workshop, January 11, 2021 36
example: pollution monitoring with IoT and blockchain A sequence of message exchanges between DLT with UEs and eNB L. D. Nguyen, A. E. Kalor, I. Leyva-Mayorga and P. Popovski, "Trusted Wireless Monitoring Based on Distributed Ledgers over NB-IoT Connectivity," in IEEE Communications Magazine, vol. 58, no. 6, pp. 77-83, June 2020 WiLab - Huawei JIC Workshop, January 11, 2021 37
example: smart data trading three trading protocols § general trading § buying on demand § selling on demand L. D. Nguyen, I. Leyva-Mayorga, A. Lewis, and P. Popovski, "Modeling and Analysis of Market Blockchain-based Data Trading in NB-IoT Networks," available at https://arxiv.org/abs/2010.06003, October 2020 WiLab - Huawei JIC Workshop, January 11, 2021 38
outlook § interaction among different generic traffic types § spectrum usage to be redefined by heterogeneity § better understanding of timing requirements § new opportunities in spatial processing § distributed ledgers and learning may fundamentally change the interactions and traffic patterns in massive IoT WiLab - Huawei JIC Workshop, January 11, 2021 39
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