Cached Packets Research Articles

Presentation and interaction of Internet of Things data based on augmented reality

In recent years, AR (Augmented Reality) technology has gradually entered people’s horizons and has become a research hotspot in the field of image processing. At the same time, the mobility and interactivity of AR have also been valued. This paper studies the interaction technology in the AR scene, and proposes a scheme to detect the user’s gaze at the cone perspective. The Leapmotion body sensor was used for gesture extension, and the hardware connection and data transmission scheme of Leapmotion and Holo Lens was designed. Based on the three input modes of sight, gesture and voice, the interaction logic between the user and the system in the AR scene is designed. The network of the Internet of Things is dominated by wireless sensor networks (Wireless Sensor Networks). This paper studies the problem of congestion in wireless sensor network sensing data transmission. WSNs nodes need to transmit the sensed data or preprocessed sensed data to sink nodes. When the data packets (or packets) received by a sensor node exceed its upper limit for forwarding or processing data packets, the excess data packets need to be buffered. When the memory of cached packets is full, excess packets are discarded, causing buffer overflows and causing node-level congestion. This paper proposes an energy balance strategy based on feedback control. The feedback control algorithm is used to adjust the node’s transmit power to realize the redistribution of node load in the network, solve the problem of node energy imbalance in wireless sensor networks, and further extend the sensor network.

CoFi: Coding-Assisted File Distribution over a Wireless LAN

The wireless channel is volatile in nature, due to various signal attenuation factors including path-loss, shadowing, and multipath fading. Existing media access control (MAC) protocols, such as the widely adopted 802.11 wireless fidelity (Wi-Fi) family, advocate masking harsh channel conditions with persistent retransmission and backoff, in order to provide a packet-level best-effort service. However, the asymmetry of the network environment of client nodes in space is not fully considered in the method, which leads to the decline of the transmission efficiency of the good ones. In this paper, we propose CoFi, a coding-assisted file distribution protocol for 802.11 based wireless local area networks (LANs). CoFi groups data into batches and transmits a random linear combination of packets within each batch, thereby reducing redundant packet and acknowledgement (ACK) retransmissions when the channel is lossy. In addition, CoFi adopts a MAC layer caching scheme that allows clients to store the overheard coded packets and use such cached packets to assist nearby peers. With this measure, it further improves the effective throughput and shortens the buffering delay when running applications such as bulk data transmission and video streaming. Our trace based simulation demonstrates that CoFi can maintain a similar level of packet delay to 802.11, but increases the throughput performance by a significant margin in a lossy wireless LAN. Furthermore, we perform a reverse-engineering on CoFi and 802.11 using a simple analytical framework, proving that they asymptotically approach different fairness measures, thus resulting in a disparate performance.

Interference Cancelation at Receivers in Cache-Enabled Wireless Networks

In this paper, we propose to exploit the limited cache packets as side information to cancel incoming interference at the receiver side. We consider a stochastic network where the random locations of base stations and users are modeled using Poisson point processes. Caching schemes to reap both the local caching gain and the interference cancelation gain for the users are developed based on two factors: the densities of different user subsets and the packets cached in the corresponding subsets. The packet loss rate (PLR) is analyzed, which depends on both the cached packets and the channel state information available at the receiver. Theoretical results reveal the tradeoff between caching resource and wireless resource. The performance for different caching schemes is analyzed, and the lowest achievable PLR for the distributed caching is investigated.

Interference Management in Cache-Enabled Stochastic Networks: A Content Diversity Approach

In wireless networks, the performance is degraded by the intensity of the interference received from concurrent transmissions. Considering a stochastic cache-enabled network where some users have caching ability to store the most popular packets, we propose a novel interference management scheme to eliminate the interference by exploiting the content diversity. First, cache-enabled users can exploit cached packets as side information to cancel the interference. Second, considering that different access points may transmit the same contents to different users simultaneously, they should be regarded as useful signals rather than interference. The performance improvement with these two content diversity schemes is theoretically analyzed in this paper. The probabilities for the interference cancellation case and the signal enhancement case are derived, respectively, followed by the investigation of the signal to interference plus noise ratio improvement with our proposed content diversity schemes. Based on this, the effective content capacity of the system is analyzed. In addition to the simulations to validate the accuracy of the theoretical analysis, the impacts of caching ability and the proposed interference management schemes on the effective content capacity are investigated.

Proactive Caching and Forwarding Schemes for Seamless Handover in IEEE WAVE Networks

The IEEE Wireless Access for Vehicular Environment (WAVE) standard consists of the IEEE 802.11p and the IEEE 1609 specifications supporting fast link establishment as well as broadband data communication in vehicular environment. Although the standard has been widely accepted by industry as well as highway authorities in many countries to be used for the radio communication infrastructure of the next-generation Intelligent Transport System (ITS), it remains open for further enhancements such as seamless handover support. This paper presents two proactive caching and forwarding schemes for seamless handover in IEEE WAVE networks: one for straight highway sections and the other for crossroads and junctions. Practical and efficient handover procedures, based on the proposed schemes, are also presented. Specifically, an on-board unit (OBU) informs the old road-side unit (RSU) about its departure from the coverage area such that the old RSU can forward the buffered packets to candidate RSUs for proactive caching. In handover scenarios around crossroads and junctions, the IEEE 802.11f Move-notify message is used by the new RSU to request the rest of candidate RSUs to purge the cached packets in order to prevent the waste of radio resource. Simulation results show that the proposed schemes outperform conventional schemes.

Rate-adaptive snoop: a TCP enhancement scheme over rate-controlled lossy links

We study TCP performance over the wireless links deploying a wireless rate-control technique, whose link characteristics are identified by variable link rate and bursty transmission error. We present a TCP enhancement scheme, called rate-adaptive snoop (RA-Snoop). RA-Snoop caches TCP packets selectively based on the wireless channel condition and the cached packets are retransmitted locally over the wireless link in case corruption loss is detected. In addition, for effective adaptation to variable bandwidth, RA-Snoop calculates the window feedback based on the bandwidth-delay product estimation and the queue level, then conveys this feedback information on the receiver's advertised window field in the acknowledgements returning to TCP sources. We compare the performance of RA-Snoop with that of existing schemes in the aspect of goodput and fairness. Results from simulations reveal that RA-Snoop achieves significant improvements over the existing schemes for various traffic scenarios.