Deterministic Communication Protocol Research Articles

Improvement of reliability in multi-interferometer-based counterfactual deterministic communication with dissipation compensation

The direct counterfactual quantum communication (DCQC) is a surprising phenomenon that quantum information can be transmitted without using any carriers of physical particles. The nested interferometers are promising devices for realizing DCQC as long as the number of interferometers goes to be infinity. Considering the inevitable loss or dissipation in practical experimental interferometers, we analyze the dependence of reliability on the number of interferometers, and show that the reliability of direct communication is being rapidly degraded with the large number of interferometers. Furthermore, we simulate and test this counterfactual deterministic communication protocol with a finite number of interferometers, and demonstrate the improvement of the reliability using dissipation compensation in interferometers.

Approximating Semi-matchings in Streaming and in Two-Party Communication

We study the streaming complexity and communication complexity of approximating unweighted semi-matchings. A semi-matching in a bipartite graph G = ( A , B , E ) with n = | A | is a subset of edges S ⊆ E that matches all A vertices to B vertices with the goal usually being to do this as fairly as possible. While the term semi-matching was coined in 2003 by Harvey et al. [2003], the problem had already previously been studied in the scheduling literature under different names. We present a deterministic one-pass streaming algorithm that for any 0 ⩽ ϵ ⩽ 1 uses space Õ( n 1+ϵ and computes an O( n (1−ϵ)/2 )-approximation to the semi-matching problem. Furthermore, with O(log n ) passes it is possible to compute an O(log n )-approximation with space Õ( n ). In the one-way two-party communication setting, we show that for every ϵ > 0, deterministic communication protocols for computing an O( n 1/(1+ϵ) c +1) -approximation require a message of size more than cn bits. We present two deterministic protocols communicating n and 2 n edges that compute an O√ n and an O(n 1/3 )-approximation, respectively. Finally, we improve on the results of Harvey et al. [2003] and prove new links between semi-matchings and matchings. While it was known that an optimal semi-matching contains a maximum matching, we show that there is a hierarchical decomposition of an optimal semi-matching into maximum matchings. A similar result holds for semi-matchings that do not admit length-two degree-minimizing paths.

Communication is Bounded by Root of Rank

We prove that any total boolean function of rank r can be computed by a deterministic communication protocol of complexity O (√ ċ log( r )). Equivalently, any graph whose adjacency matrix has rank r has chromatic number at most 2 O (√ r ċlog( r )) . This gives a nearly quadratic improvement in the dependence on the rank over previous results.

Emulation-based stabilization of networked control systems implemented on FlexRay

We investigate the emulation controller design approach for nonlinear networked control systems (NCS) with FlexRay. FlexRay is a deterministic communication protocol which is increasingly used in the automotive industry as it provides a high bandwidth and allows for safety critical applications. It is characterized by pre-set communication cycles that are subdivided into static and dynamic segments; the data transmissions are scheduled by different rules depending on the segment. We propose for the first time a hybrid model of NCS with FlexRay for this purpose. We show, under reasonable assumptions, that the asymptotic stability property ensured by the controller in the absence of communication constraints is preserved when the latter is implemented over FlexRay with sufficiently frequent data transmission. In particular, we assume that on each communication segment, the data transmissions are governed by uniformly globally exponentially stable protocols. This covers the case when the round-robin protocol is implemented on the static segment and the try-once-discard protocol is implemented on the dynamic segment. We provide explicit maximum allowable transmission interval bounds that guarantee stability.

On time-triggered and event-based control of integrator systems over a shared communication system

When analyzing networked control systems, where the control loop is closed over a communication system, it is crucial to take the communication system into account. Hence, time-triggered and event-based control of an integrator system with noise over a shared communication system is analyzed. Thereby, analytical models of different communication systems are used and the analysis is focused on the effect of the communication system on the performance, as well as the interaction between control and communication. For time-triggered control, where the event times are known in advance, a deterministic communication protocol can be used. Hence, time-triggered control with the two most well-known deterministic communication protocols, time division multiple access (TDMA) and frequency division multiple access (FDMA), is analyzed. For event-based control, where the events appear at random times, a contention-based communication protocol should be used. Hence, event-based control is analyzed with different contention-based communication protocols: pure ALOHA, slotted ALOHA, a queueing system, and Erlang’s loss model. It turns out that time-triggered control with either TDMA or FDMA outperforms event-based control with pure or slotted ALOHA. However, event-based control with a properly designed queueing system gives an even better performance. Thus, we conclude that it is crucial to take the details of the communication system into account.

Deterministic end-to-end delay analysis in an avionics network

Avionics Full DupleX Switched Ethernet is a deterministic communication protocol for distributed embedded real-time applications over asynchronous channels. It is a promising technique that can replace the existing avionics data buses, such as ARINC429 and MIL-STD-1553B. One of the key challenges for deploying and maintaining Avionics Full DupleX Switched Ethernet is to determine the end-to-end transmission delay in such a network. This article aims at handling this challenge effectively applying a completely theoretical analysis. An analytical method based on the network calculus theory is presented in detail to calculate the end-to-end transmission delay in an Avionics Full DupleX Switched Ethernet network, which consists of many interconnect nodes with different scheduling disciplines. Further, this approach is improved by taking into account the effects of source node initial jitter and first in, first out optimization. Additionally, a Matlab/TrueTime simulation platform is constructed to verify the effectiveness of the method. Simulation results show that switches with advanced scheduling algorithms, i.e. static priority scheduling, can significantly improve the delay performance in a multi-hop network.

Confidential Deterministic Quantum Communication Using Three Quantum States

A secure quantum deterministic communication protocol is described. The protocol is based on transmission of quantum states from unbiased bases and exploits no entanglement. It is composed form two main components: a quantum quasi secure quantum communication supported by a suitable classical message preprocessing layer. Contrary to many others propositions, it does not require large quantum registers. A security level comparable to classic block ciphers is achieved by a specially designed, purely classic, message pre- and post-processing. However, unlike to the classic communication, no key agreement is required. The protocol is also designed in such a way, that noise in the quantum channel works in advantage to legitimate users improving the security level of the communication.

Sample Spaces with Small Bias on Neighborhoods and Error-Correcting Communication Protocols

We give a deterministic algorithm which, on input an integer n , collection \cal F of subsets of {1,2,\ldots,n} , and ɛ∈ (0,1) , runs in time polynomial in n| \cal F |/ɛ and produces a \pm 1 -matrix M with n columns and m=O(log | \cal F |/ɛ 2 ) rows with the following property: for any subset F ∈ \cal F , the fraction of 1's in the n -vector obtained by coordinatewise multiplication of the column vectors indexed by F is between (1-ɛ)/2 and (1+ɛ)/2 . In the case that \cal F is the set of all subsets of size at most k , k constant, this gives a polynomial time construction for a k -wise ɛ -biased sample space of size O(log n/ɛ 2 ) , compared with the best previous constructions in [NN] and [AGHP] which were, respectively, O(log n/ɛ 4 ) and O(log 2 n/ɛ 2 ) . The number of rows in the construction matches the upper bound given by the probabilistic existence argument. Such constructions are of interest for derandomizing algorithms. As an application, we present a family of essentially optimal deterministic communication protocols for the problem of checking the consistency of two files.