经典信道与经典-量子信道容量的解析计算公式

Classical Capacities of Averaged and Compound Quantum Channels

We determine the capacity of compound classical-quantum channels. As a consequence we obtain the capacity formula for the averaged classical-quantum channels. The capacity result for compound channels demonstrates, as in the classical setting, the existence of reliable universal classical-quantum codes in scenarios where the only a priori information about the channel used for the transmission of information is that it belongs to a given set of memoryless classical-quantum channels. Our approach is based on the universal classical approximation of the quantum relative entropy which in turn rel…

Trade-off capacities of the quantum Hadamard channels

Coding theorems in quantum Shannon theory express the ultimate rates at which a sender can transmit information over a noisy quantum channel. More often than not, the known formulas expressing these transmission rates are intractable, requiring an optimization over an infinite number of uses of the channel. Researchers have rarely found quantum channels with a tractable classical or quantum capacity, but when such a finding occurs, it demonstrates a complete understanding of that channel's capabilities for transmitting classical or quantum information. Here, we show that the three-dimensional …

Quantum Channel Capacities Per Unit Cost

Communication over a noisy channel is often conducted in a setting in which different input symbols to the channel incur a certain cost. For example, for bosonic quantum channels, the cost associated with an input state is the number of photons, which is proportional to the energy consumed. In such a setting, it is often useful to know the maximum amount of information that can be reliably transmitted per cost incurred. This is known as the capacity per unit cost. In this paper, we generalize the capacity per unit cost to various communication tasks involving a quantum channel such as classica…

RF-based Energy Harvesting in Decode-and-Forward Relaying Systems: Ergodic and Outage Capacities

Radio-frequency energy harvesting constitutes an effective way to prolong the lifetime of wireless networks, wean communication devices off the battery and power line, benefit the energy saving and lower the carbon footprint of wireless communications. In this paper, an interference aided energy harvesting scheme is proposed for cooperative relaying systems, where energy-constrained relays harvest energy from the received information signal and co-channel interference signals, and then use that harvested energy to forward the correctly decoded signal to the destination. The time-switching sche…

Maximum Likelihood Upper Bounds on the Capacities of Discrete Information Stable Channels

Motivated by a greedy approach for generating {\it{information stable}} processes, we prove a universal maximum likelihood (ML) upper bound on the capacities of discrete information stable channels, including the binary erasure channel (BEC), the binary symmetric channel (BSC) and the binary deletion channel (BDC). The bound is derived leveraging a system of equations obtained via the Karush-Kuhn-Tucker conditions. Intriguingly, for some memoryless channels, e.g., the BEC and BSC, the resulting upper bounds are tight and equal to their capacities. For the BDC, the universal upper bound is rela…

不可控有限状态信道在有/无反馈情况下的容量上界

Upper Bounds on the Capacities of Noncontrollable Finite-State Channels with/without Feedback

通过将延迟信道状态视为信道输入的一部分，定义新信道输入与输出之间的定向信息率，推导不可控有限状态信道在有/无反馈情况下的容量上界，并转化为有限状态和动作的平均每阶段随机控制问题，通过值迭代求解。

General non-asymptotic and asymptotic formulas in channel resolvability and identification capacity and their application to wire-tap channel

Several non-asymptotic formulas are established in channel resolvability and identification capacity, and they are applied to wire-tap channel. By using these formulas, the $ε$ capacities of the above three problems are considered in the most general setting, where no structural assumptions such as the stationary memoryless property are made on a channel. As a result, we solve an open problem proposed in Han & Verdu and Han. Moreover, we obtain lower bounds of the exponents of error probability and the wire-tapper's information in wire-tap channel.

单标签设置下DNA标记的容量研究

On the Capacity of DNA Labeling in the Single-Label Setting

本文通过将DNA标记建模为确定性信道，证明其零错误容量等于标记容量，推导出所有星图的零错误容量，从而完整刻画单标签设置下的标记容量，并给出容量可达码的构造方法及容量范围。

Capacity of the Trapdoor Channel with Feedback

We establish that the feedback capacity of the trapdoor channel is the logarithm of the golden ratio and provide a simple communication scheme that achieves capacity. As part of the analysis, we formulate a class of dynamic programs that characterize capacities of unifilar finite-state channels. The trapdoor channel is an instance that admits a simple analytic solution.

有限机制下的可变最小割最大流界与算法

Variable Min-Cut Max-Flow Bounds and Algorithms in Finite Regime

本文针对链路容量波动的异构网络，提出基于计算几何的有限机制分析框架，推导新性能界并证明增加链路可降低近90%吞吐量波动，同时给出O(|E|^2+|V|)稳定性算法及AR-RLNC延迟-吞吐量缓解方案。

Quantum capacity under adversarial quantum noise: arbitrarily varying quantum channels

We investigate entanglement transmission over an unknown channel in the presence of a third party (called the adversary), which is enabled to choose the channel from a given set of memoryless but non-stationary channels without informing the legitimate sender and receiver about the particular choice that he made. This channel model is called arbitrarily varying quantum channel (AVQC). We derive a quantum version of Ahlswede's dichotomy for classical arbitrarily varying channels. This includes a regularized formula for the common randomness-assisted capacity for entanglement transmission of an …