This work introduces a new model for cloud gaming systems aimed at optimizing the timeliness of video frames based on an age of information (AoI) metric. Mobile clients submit actions through an access network to a game server. The game server generates video frames at a constant frame rate. At the mobile device, the display of these frames represent game status updates. We develop a Markov model to characterize the frame delivery process in low-latency edge cloud gaming systems. Based on this model, we derive a simple formula for the average status age of a tightly synchronized low-latency mobile gaming system in which the inter-frame period is a significant contributor to the system latency. We validate the model by ns-3 simulation of a low-latency edge cloud gaming system. Our evaluation scenarios included single-player games as well as multi-player games in which the game processing was conducted by a combination of a centralized game server and edge cloud renderers.

There has been a considerable interest in quantifying the influence that one node exerts on another in a social network. Using directed information, we study the problem for a simple, two-node network that models two users in a Twitter network in which one user (Alice) influences the other user (Bob) through her tweets. Under this setup, we relate the problem of direction of influence to the calculation of directed information from the input to the output in a bufferless single-server timing queue. Based on this relationship, we compute the directed information rate from Alice to Bob and, under simplifying assumptions, relate that rate to the distributions of Alice's tweet timings and Bob's action timings.

In this paper, the design and analysis of a new bandwidth-efficient signaling method over the bandlimited intensity-modulated direct-detection (IM/DD) channel is presented. The channel can be modeled as a bandlimited channel with nonnegative input and additive white Gaussian noise (AWGN). Due to the nonnegativity constraint, standard methods for coherent bandlimited channels cannot be applied here. Previously established techniques for the IM/DD channel require bandwidth twice the required bandwidth over the conventional coherent channel. We propose a method to transmit without intersymbol interference in a bandwidth no larger than the bit rate. This is done by combining Nyquist or root-Nyquist pulses with a constant bias and using higher-order modulation formats. In fact, we can transmit with a bandwidth equal to that of coherent transmission. A trade-off between the required average optical power and the bandwidth is investigated. Depending on the bandwidth required, the most power-efficient transmission is obtained by the parametric linear pulse, the so-called "better than Nyquist" pulse, or the root-raised cosine pulse.

In this paper, the design and analysis of a new bandwidth-efficient signalling method over the bandlimited intensity-modulated direct-detection (IM/DD) channel is proposed. The channel can be modeled as a bandlimited channel with nonnegative input and additive white Gaussian noise. Due to the nonnegativity constraint, the methods previously proposed for conventional bandlimited channels cannot be applied here. We propose a method to transmit without intersymbol interference in a narrower bandwidth compared to previous works, by combining Nyquist pulses with a constant bias. In fact, we can transmit with a bandwidth equal to that of coherent transmission. A trade-off between the required average optical power and the bandwidth is investigated. At low bandwidths, the most power-efficient transmission is obtained by either the parametric linear pulse or the so-called "better than Nyquist" pulse, depending on the exact bandwidth.