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Performance evaluation of pulse-based multiplexing protocol implemented on massive IoT devices
Abstract
An Internet of Things (IoT) employing resource-restricted (e.g., battery-limited) IoT devices at high densities will require an effective multiplexing protocol that can be implemented with low energy consumption, while being able to effectively avoid collisions between the transmissions from multiple IoT devices. Asynchronous Pulse-Code Multiple Access (APCMA) has been proposed as a communication protocol based on pulse-encoded signals that allows multiple senders to simultaneously transmit their messages. Even if multiple messages on the same band overlap in time during transmission, they are disentangled at the receiver by a decoding algorithm that is based on pattern matching of pulse trains. In this paper, we implement the APCMA protocol on an FPGA and evaluate its performance in wireless communication. We also implement a decoding algorithm that matches pulses by logical operations on a shift register. Our experiments show that the APCMA protocol can realize multiplexing with low overhead and that the error rate caused by misdetection during decoding is reduced with longer pulse trains.
... This makes code words quite long, thus increasing delay of messages. On the other hand, it also increases the sparsity of code words, which gives it the potential to allow thousands of devices to transmit at the same time [10,11,14,15]. ...
... Decoding of messages at the receiver is conducted by pattern recognition algorithms that use either a type of finite automata operating on pulse sequences [9,11] or a shift register that detects pulse sequences that are input at the left side of the register and that shift one cell to the right each time step [14,15]. ...
... APCMA has been implemented on various hardware platforms, including the Arduino Mega 2560 microcontroller [11] and the Xilinx Spartan-3E FPGA [10,14,15]. APCMA has also been implemented and tested for the distribution of power packets in a small electric power network [16]. ...
While the Internet of Things (IoT) is usually envisioned to support powerful functionality, like in self-driving cars, there is also increasing interest in simpler IoT applications that can be employed on massive scales at high densities, like in data gathering at meetings with large audiences. The latter vision requires low-cost devices consuming little energy, and it tends to come with a relaxed need for high-speed communication. Its realization necessitates the development of wireless protocols that are simple, yet that can effectively arbitrate multi-access to communication channels. Carrier-Sense Multiple Access with Collision Avoidance (CSMA/CA) is usually deployed in such contexts, but it tends to work less well when large numbers of nodes attempt to simultaneously access a wireless channel. Asynchronous Pulse Code Multiple Access (APCMA) has been developed with simultaneous asynchronous access to communication channels in mind by using a sparse representation of pulses to encode messages, but being relatively recent, its performance has never been systematically compared to CSMA/CA. This paper compares APCMA’s performance with that of CSMA/CA in terms of the success probability (i.e., absence of errors) of message transmissions through the use of simulations and analytical models, under the assumption of equivalence in throughput. We find that APCMA with four pulses per code word performs worse than CSMA/CA, but the roles are reversed if five or six pulses are used.
... The transmitter and receiver contain the same table of pulse-based codewords, whereby the presence of a pulse in a certain time slot is encoded by a 1 and its absence by a 0. One possible algorithm for decoding APCMA messages uses a shift register at the receiver [6]. Each cell in this shift register represents one time slot, whereby a pulse is encoded as a 1 if its power exceeds a threshold, otherwise it is encoded as a 0. The contents of the register shift to the right each clock cycle, whereby each new incoming pulse enters the register from the left. ...
... Based on an implementation of OOK-APCMA on an FPGA, an experiment with 100 devices was conducted in [6]. Some LPWA systems, such as LoRa and ELTRES, use CSS to improve detection performance and enable widearea communications up to tens of kilometers in distance. ...
Asynchronous Pulse Code Multiple Access (APCMA) is a pulse-based communication system for massive IoT. It enables high-density communication because it can decode messages with a high probability even if they collide. We evaluate the performance of APCMA with Chirp Spread Spectrum-modulated pulses (CSS-APCMA) by comparing it with On-Off Keying APCMA (OOK-APCMA) and LoRa. Our first experiment shows that APCMA has a lower packet error rate (PER) than LoRa in a congested environment. Our second experiment shows that CSS-APCMA has a smaller PER than OOK-APCMA in a noisy environment. Our results confirm that CSS-APCMA is suitable for massive IoT.
... The decoding of messages at the receiver is done by a pattern recognition algorithm using either a finite automaton that operates on pulse sequences [34], [36], or a shift register that detects pulse sequences entering at the left and shifting one cell to the right each time step [37], [38]. ...
The Internet of Things (IoT) has revolutionized the way we interact with everyday objects by connecting sensors/actuators to the Internet to monitor and control various aspects of our environment. As the number of IoT devices continues to grow, efficient medium access control protocols are needed to ensure that communication takes place in a reliable and scalable manner. In this paper, we investigate the performance of the Asynchronous Pulse Code Multiple Access (APCMA) protocol in massive IoT scenarios through simulations and analysis. We show that APCMA is able to outperform CSMA/CA in terms of the number of successfully transmitted messages in scenarios with up to 30,000 transmitting sensor nodes while also being able to utilize the channel more efficiently. We also examine the sensitivity of APCMA’s performance with respect to its parameters.
... The receiver first detects whether there is a pulse in each time slot and converts the received signal into a pulse train, assigning a "1" to a detected slot and a "0" to an undetected slot. There are two decoding schemes from pulse trains to received data: one is spike automaton [8] and the other is using a shift register [1], [9], which is the algorithm used in this paper. The shift register is a method where decoding is performed by shifting the pulse train by one slot at each clock cycle and comparing it with all available codewords. ...
For the realization of an Internet of Things (IoT) with high densities of devices it is necessary that wireless communication protocols are developed that offer (1) low energy consumption, (2) simplicity of encoding and decoding, (3) an asynchronous mode of communication, and (4) an effective but simple method to deal with interference between transmissions. This paper presents the implementation, experimentation, and analysis of a protocol on the MAC sublayer that encodes information in terms of silent intervals between pulses. Based on the representation of patterns of sparse pulses, this encoding has the potential for extremely low power consumption at the transmitter side. It also results in only few conflicts between messages that are broadcast on the same band overlapped in time, while no synchronization between transmitters and receivers is necessary. The protocol is demonstrated experimentally on the 315 MHz band with 100 senders and one receiver configured in a Star topology. Theoretical analysis confirms that the probability of conflicts between messages is low, even if the number of devices increases to the order of ten thousand. This protocol facilitates the implementation of IoT devices that are restricted in terms of hardware and energy resources.
A power packet dispatching system is expected to be one of the advanced power distribution systems for controlling electric power, providing energy on demand, and reducing wasted energy consumption. In this paper, power packet routers are designed and experimentally verified for realizing a networked power packet distribution system. While the previously developed router directly forwards the power packet to a load, the new router forwards the packet to the other router with an information tag reattached to the power payload. In addition, the new router can adjust the starting time for forwarding the received power packet to the other site, thus utilizing storage capacity integrated into the router. The results successfully clarify the feasibility of the power packet distribution network.
Wireless sensor networks (WSNs) are typically characterized by a limited energy supply at sensor nodes. Hence, energy efficiency is an important issue in the system design and operation of WSNs. In this paper, we introduce a novel communication paradigm that enables energy-efficient information delivery in wireless sensor networks. Compared with traditional communication strategies, the proposed scheme explores a new dimension - time, to deliver information efficiently. We refer to the strategy as Communication through Silence (CtS). We identify a key drawback of CtS - energy - throughput trade-off, and explore optimization mechanisms that can alleviate the trade-off. We then present several challenges that need to be overcome, primarily at the medium access control layer of the network protocol stack, in order to realize CtS effectively.
Asynchronous Pulse-Code Multiple Access (APCMA) has been proposed as a brain-inspired communication protocol based on pulse-like signals (Peper et al, The Brain & Networks, 2018). Encoding data as intervals between pulses, APCMA allows multiple transmitters to transmit pulse trains at arbitrary times. While this typically causes collisions in conventional multiple access protocols, it does not do so in APCMA. Even if pulse trains collide and a receiver receives a mixture of them, they are disentangled by a demodulation algorithm that is based on a spike automaton, which is a type of finite automaton that is designed to recognize specific sequences of pulses. This makes APCMA especially suitable for data multiplexing in a communication system that lacks carrier-sense functionality. In this paper, we apply the APCMA protocol to an electrical power packet routing system. The power packet router lacks carrier-sense functionality, which would be necessary for transmission from multiple sources in a conventional communication protocol. We design and implement the modulation and the demodulation protocols of APCMA on a FPGA in power packet router devices. Our experimental results show that the proposed APCMA-based power routing system can transmit multiple power packets simultaneously without collisions.
A power packet dispatching system and power packet routers with the power storages have been developed. The system is expected to reduce the number of wires, to provide energy on demand and to be applied to various system working with battery such as electric vehicles, robots and so on. In the previous studies, when a router receives a power packet, it is temporarily charged to the storage and immediately transferred to another router or a load. In this paper, we propose more flexible routing protocol for power packet dispatching systems. We have designed a novel protocol with several commands to operate the routers, to charge power to a storage of a router, to reproduce power packets using the charged power, and so on. We have implemented the proposed protocol on the power packet routers and shown that our protocol can transmit the power packets flexibly.
Brain-like communication based on spikes has potential advantages in terms of energy consumption, but it is unclear what type of encoding of information allows good robustness to errors. This paper shows how to construct Error Correcting Codes that are particularly applicable to spike-based signals. We adopt an encoding based on Inter-Spike Intervals, and show how the addition of a few “check” spikes makes the codes robust to interference with other spikes. Key in our construction is the use of finite automata that are adapted to recognize specific spike trains. Once the first few spikes are received by such spike automata, they can predict the timing of subsequent spikes, and use this prediction to test whether a spike train is a valid message or not. The proposed spike encoding may find application in wireless sensor networks, in which low energy consumption rather than high data rates is a priority.
Wireless communication is indispensable to Internet of Things (IoT). Carrier sensing multiple access/collision avoidance (CSMA/CA) is a well-proven wireless random access protocol and allows each node of equal probability in accessing wireless channel, which incurs equal throughput in long term regardless of the channel conditions. To exploit node diversity that refers to the difference of channel condition among nodes, this paper proposes two opportunistic random access mechanisms: overlapped contention and segmented contention, to favor the node of the best channel condition. In the overlapped contention, the contention windows of all nodes share the same ground of zero, but have different upper bounds upon channel condition. In the segmented contention, the contention window upper bound of a better channel condition is smaller than the lower bound of a worse channel condition; namely, their contention windows are segmented without any overlapping. These algorithms are also polished to provide temporal fairness and avoid starving the nodes of poor channel conditions. The proposed mechanisms are analyzed, implemented, and evaluated on a Linux-based testbed and in the NS3 simulator. Extensive comparative experiments show that both opportunistic solutions can significantly improve the network performance in throughput, delay, and jitter over the current CSMA/CA protocol. In particular, the overlapped contention scheme can offer 73.3% and 37.5% throughput improvements in the infrastructure-based and ad hoc networks, respectively.
After deregulation, there are many entities, such as IOUs
(investor owned utilities) IPPs, marketers, aggregators, ISO and
security coordinator in power industries. This paper discusses two
topics of cooperative operations among IOUs and IPPs. One is an
ecological model to simulate the market power of IOU and IPP based on
Lotka-Volterra competition model. We can demonstrate the share
competition of IOU and LPP by using this model. The co-evolution model
of electricity price among IOU and IPP is also introduced. Another is a
supplementary power network which makes it possible for many types of
dispersed generation plants to generate effectively and to participate
in a market circumstance without disadvantages of existing power
utilities. This power network is called OEEN (open electric energy
network) because the network is open to the many entities with respect
to the small scale transactions. Elements of OEEN system are dispersed
energy storage devices, load controllers and a data communication link.
In OEEN system, a transaction power is treated as an energy package
wrapped with an information tag. We call this concept as an
electricity-power-packet (EPP). These concepts are discussed in the
paper
4e-2012-IEEE Standard for Local and metropolitan area networks-Part 15.4: Low-Rate Wireless Personal Area Networks (LR-WPANs) Amendment 1: MAC sublayer
IEEE, 802.15.4e-2012-IEEE Standard for Local and metropolitan area networks-Part 15.4: Low-Rate Wireless Personal Area Networks (LR-WPANs) Amendment 1: MAC sublayer, 2012.