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Showing papers on "Fast packet switching published in 2017"


Journal ArticleDOI
TL;DR: The analytical and simulation results show that the proposed relay selection scheme has not only significant gain in outage performance but also similar average packet delay when the channel signal-to-noise ratio (SNR) is high enough, making it an attractive scheme in practice.
Abstract: Applying data buffers at relay nodes significantly improves the outage performance in relay networks, but the performance gain is often at the price of long packet delays. In this paper, a novel relay selection scheme with significantly reduced packet delay is proposed. The outage probability and average packet delay of the proposed scheme under different channel scenarios are analyzed. Simulation results are also given to verify the analysis. The analytical and simulation results show that, compared with non-buffer-aided relay selection schemes, the proposed scheme has not only significant gain in outage performance but also similar average packet delay when the channel signal-to-noise ratio (SNR) is high enough, making it an attractive scheme in practice.

95 citations


Journal ArticleDOI
TL;DR: In this paper, a dynamic quantiser is introduced, which is composed of a dynamic scaling and a static quantiser, and a switching strategy which combines average dwell time switching with event-driven switching is proposed.
Abstract: The problem of fault detection for switched systems with quantisation effects and packet dropout is presented in this study. A dynamic quantiser is introduced, which is composed of a dynamic scaling and a static quantiser. Since a novel switched system is modelled according to packet dropout, a switching strategy which combines average dwell time switching with event-driven switching is proposed. The systems performance and the relationship between the switching signal and the packet dropout rate are simultaneously developed. Furthermore, sufficient conditions for the existence of fault detection filters are given in the framework of linear matrix inequality, and the filter gains and the quantiser range are derived by a convex optimised method. Finally, two illustrative examples demonstrate the effectiveness of the proposed method.

31 citations


Journal ArticleDOI
TL;DR: A joint spatial super-channel optical packet switching (OPS) scheme that increases the granularity of SDM-WDM optical networks and simplifies the hardware of an OPS system is proposed.
Abstract: Novel optical networking technologies are necessary to efficiently utilize the huge transmission capacity of spatial division multiplexing wavelength division multiplexing (SDM-WDM) optical networks. In this paper, we propose a joint spatial super-channel optical packet switching (OPS) scheme that increases the granularity of SDM-WDM optical networks. This joint switching concept simplifies the hardware of an OPS system. We experimentally investigate a 100 Gb/s spatial-spectral super-channel OPS system and present the preliminary results of the demonstration showing error-free switching operation. Finally, we discuss the benefits of this scheme in terms of the number of devices and the influence of the propagation time deviation between multiple optical payloads of a spatial super-channel optical packet from the viewpoint of the bandwidth utilization efficiency on the system.

20 citations


Journal ArticleDOI
TL;DR: This work introduces a new optical transport concept that combines packet aggregation with a multipoint-to-point line coding and FEC processing and avoids the quadratic full mesh scalability problem of other aggregated switching technologies such as, e.g., wavelength switching.
Abstract: Enhanced flexibility in optical transport networks is a key requirement to support dynamic traffic load in packet-based networks. Today, flexibility is achieved by packet switches linked by static point-to-point transport connections. Wide-stretched synchronization patterns, line coding schemes, and forward error correction (FEC) frames prohibit flexibility right at the transport layer. We introduce a new optical transport concept that combines packet aggregation with a multipoint-to-point line coding and FEC processing. This concept avoids the quadratic full mesh scalability problem of other aggregated switching technologies such as, e.g., wavelength switching. It combines the flexibility of a distributed Ethernet switch and the performance of a leading edge optical transport system.

15 citations


Proceedings ArticleDOI
17 Mar 2017
TL;DR: To detect such a packet leak, this paper presents a cost effective authentication design where the packet source and destination addresses are tagged with a dynamic random value and the tag is scrambled with the packet data.
Abstract: Packet leak on network-on-chip (NoC) is one of the key security concerns in the MPSoC design, where the NoC of the system can come from a third-party vendor and can be illegitimately implanted with hardware trojans. Those trojans are usually small so that they can escape the scrutiny of circuit level testing and perform attacks when activated. This paper targets the trojan that leaks packets to malicious applications by altering the packet source and destination addresses. To detect such a packet leak, we present a cost effective authentication design where the packet source and destination addresses are tagged with a dynamic random value and the tag is scrambled with the packet data. Our design has two features: 1) If the adversary attempts to play with tag to escape detection, the data in the packet may likely be changed -- hence invalidating the leaked packet; 2) If the attacker only alters the packet addresses without twiddling tag in the packet, the attack will be100% detected.

14 citations


Journal ArticleDOI
TL;DR: This paper surveys research on mathematical models that predict the performance of digital devices that operate with intermittent energy sources and discusses probability models based on Markov chains that can be used to predict the effective rates at which such devices operate.
Abstract: This paper surveys research on mathematical models that predict the performance of digital devices that operate with intermittent energy sources. The approach taken in this work is based on the “Energy Packet Network” paradigm where the arrival of data to be processed or transmitted, and the energy to operate the system, are modeled as discrete random processes. Our assumption is that these devices will capture energy from intermittent ambient sources such as vibrations, heat or light, and capture it onto electrical energy that may be stored in batteries or capacitors. The devices consume this energy intermittently for processing and for wired or wireless transmission. Thus, both the arrival of energy to the device, and the devices workload, are modeled as random processes. Based on these assumptions, we discuss probability models based on Markov chains that can be used to predict the effective rates at which such devices operate. We also survey related work that models networks of such systems.

13 citations


Patent
Cai Hui1, Hu Weiqi1
10 May 2017
TL;DR: In this paper, the authors present a packet control method, switch and controller, where the switch receives a packet, and processes the packet according to pipelining, wherein the original packet is stored in a buffer and a buffer identifier is used for identifying the buffer location.
Abstract: The present invention discloses a packet control method, switch and controller. The method includes: the switch receives a packet, and processes the packet according to pipelining, wherein the original packet is stored in a buffer and a buffer identifier is used for identifying the buffer location of the original packet; when the packet fails to match a stream table, the switch transmits, to the controller, a first packet message Packet_in which carries the buffer identifier, all or part of the content of the packet, an input port number, and information obtained during the packet processing; the switch receives, transmitted from the controller, a second packet message Packet_out which carries the buffer identifier and a packet processing instruction including indication information of a designated stream table; following the packet processing instruction, the switch re-processes the packet from the designated stream table. With this means, the switch can flexibly process the packet according to the instruction of the controller.

9 citations


Journal ArticleDOI
TL;DR: This paper considers a MANET with constraints on both buffer size and packet lifetime and explores the impacts of such constraints on network performance.
Abstract: While scaling law results on the performance of mobile ad hoc networks (MANETs) have been extensively reported in literature, the exact performance of such networks, particularly their real achievable performance under practical network constraints, is still largely unexplored. As one step toward practical performance study for MANETs, this paper considers a MANET with constraints on both buffer size and packet lifetime and explores the impacts of such constraints on network performance. Analysis on the exact throughput capacity of the network is first provided to reveal its maximum possible and input rate-independent throughput performance. With the help of the embedded Markov chain theory, a complete theoretical framework is then developed, which enables the achievable and input rate-dependent throughput and packet loss ratio to be derived in closed form under any exogenous rate. Based on the $M/G/1/K$ queueing theory, the packet end-to-end delay under any exogenous rate is further studied to give a relatively whole picture on how buffer size and packet lifetime impact the network throughput, packet loss ratio, and packet delay.

8 citations


Journal ArticleDOI
TL;DR: The approach employs capacity limits and Markov chain models of fading to give analytical results on the throughput achieved by adaptive transmission in packet radio systems.
Abstract: Analytical methods are provided for use in performance evaluations, tradeoff studies, and preliminary designs of adaptive modulation and coding protocols that obtain their control information from practical sources. Our approach employs capacity limits and Markov chain models of fading to give analytical results on the throughput achieved by adaptive transmission in packet radio systems. The analytical methods replace simulations of the modem, iterative decoder, and time-varying fading channel. The amount of processor time required for protocol performance evaluations is decreased by several orders of magnitude.

8 citations


Journal ArticleDOI
TL;DR: A hybrid technique is proposed to utilize the advantages of both APC and PC while attempting to remove the limitation of both in the proposed technique, applications of APC-PC on Gilbert two state model has been studied.
Abstract: In an automatic repeat request (ARQ) scheme, a packet is retransmitted if it gets corrupted due to transmission errors caused by the channel. However, an erroneous packet may contain both erroneous bits and correct bits and hence it may still contain useful information. The receiver may be able to combine this information from multiple erroneous copies to recover the correct packet. Packet combining (PC) is a simple and elegant scheme of error correction in transmitted packet, in which two received copies are XORed to obtain the bit location of erroneous bits. Thereafter, the packet is corrected by bit inversion of bit located as erroneous. Aggressive packet combining (APC) is a logic extension of PC primarily designed for wireless communication with objective of correcting error with low latency. PC offers higher throughput than APC, but PC does not correct double bit errors if occur in same bit location of erroneous copies of the packet. A hybrid technique is proposed to utilize the advantages of both APC and PC while attempting to remove the limitation of both. In the proposed technique, applications of APC-PC on Gilbert two state model has been studied. The simulation results show that the proposed technique offers better throughput than the conventional APC and lesser packet error rate than PC scheme.

7 citations


Proceedings ArticleDOI
01 Mar 2017
TL;DR: An R-tree based parallel many-field packet classification technique using multi-threading to classify packet into the flow it belongs to using a parallelism packet classification scheme is proposed.
Abstract: Network packet classification is important network kernel function to enables various network services such as Quality of Service (QoS), security and resource reservation. The OpenFlow protocol is the responsible of the packet classification, it uses a set of rules called ruleset, each rule in that rule set contain a set of matching fields. With the rapid growing of rulesets size and rule fields numbers in the modern networks, it became so difficult to classify incoming packets at reasonable speed using the classical packet classification techniques. Many modern software-based classification solutions have been proposed to accelerate packet classification in additional to hardware-based solutions. In general, to design packet classification algorithm, it is important to strike a balance between high throughput and low memory requirements. This paper proposes an R-tree based parallel many-field packet classification technique using multi-threading to classify packet into the flow it belongs to; Multi-threading has been employed to accelerate packet classification by introduce a parallelism packet classification scheme. Two main algorithms that represent the main two parts of the proposed technique have been described, first algorithm describes how to constructing R-tree from the corresponding ruleset, and the other algorithm describes the R-tree querying in parallel manner. The performance of the proposed technique has been evaluated with consideration of throughput, latency, and memory access by testing the proposed many-fields packet classification algorithms on Class-Bench rulesets. Experiment results showed that the proposed parallel query algorithm can classify packets with very good throughput, latency, and memory access compared with other many-fields packet classification solutions.

Proceedings ArticleDOI
18 Jun 2017
TL;DR: A persistent kernel based software architecture is proposed to overcome the challenges inherent in GPU implementation like kernel invocation overhead, CPU-GPU communication and memory access overhead, and to reduce the packet latency on average by a factor of 3.5.
Abstract: In response to the tremendous growth of the Internet, towards what we call the Internet of Things (IoT), there is a need to move from costly, high-time-to-market specific-purpose hardware to flexible, low-time-to-market general-purpose devices for packet processing. Among several such devices, GPUs have attracted attention in the past, mainly because the high computing demand of packet processing applications can, potentially, be satisfied by these throughput-oriented machines. However, another important aspect of such applications is the packet latency which, if not handled carefully, will overshadow the throughput benefits. Unfortunately, until now, this aspect has been mostly ignored. To address this issue, we propose a method that considers the variable bit rate of the traffic and, depending on the current rate, minimizes the latency, while meeting the rate demand. We propose a persistent kernel based software architecture to overcome the challenges inherent in GPU implementation like kernel invocation overhead, CPU-GPU communication and memory access overhead. We have chosen packet classification as the packet processing application to demonstrate our technique. Using the proposed approach, we are able to reduce the packet latency on average by a factor of 3.5, compared to the state-of-the-art solutions, without any packet drop.

Patent
Shinji Yamashita1, Akiko Yamada1
10 Aug 2017
TL;DR: In this article, a packet transmission apparatus including a memory and a processor coupled to the memory and the processor configured to output the packet, when an identifier of the input port is stored in the memory, from the output port associating with the input ports, and perform the packet process.
Abstract: There is provided a packet transmission apparatus including: a memory in which identification information of a packet and information of a packet process for operating on the packet are stored in association, and identifiers of an input port to which the packet is input and an output port from which the packet is output are stored in association; and a processor coupled to the memory and the processor configured to: output the packet, when an identifier of the input port is stored in the memory, from the output port associating with the input port, and perform the packet process, when the identifier of the input port is not stored in the memory, based on the identification information and the information of the packet process stored in the memory.

Journal ArticleDOI
TL;DR: An exact analytical model for single-wavelength quality of service (QoS) differentiation in a two-class optical packet switch is presented and it is shown that it is possible to direct almost all the packet losses to the low-priority class under moderate loads.
Abstract: We present an exact analytical model for single-wavelength quality of service (QoS) differentiation in a two-class optical packet switch. In this system, QoS differentiation is achieved by limiting the set of fiber delay lines (FDLs) to the low-priority class, whereas the high-priority class is allowed to access the entire FDL bank. The analytical model is based on multi-regime Markov fluid queues and is extensible to multi-class systems with more than two classes. Markovian arrival process packet arrivals and phase-type distributed packet sizes are considered for the purpose of generality. The proposed analytical model is validated through simulations. The numerical results provide insight into determining appropriate subsets of FDLs allowed for the access of the low-priority class. The results also show that it is possible to direct almost all the packet losses to the low-priority class under moderate loads.

Proceedings ArticleDOI
15 May 2017
TL;DR: The relationship among network scale, granularity and latency is investigated, and the use of the proposed fine-grained optical time slice switching (OTSS) in DC and HPC networks over arbitrary topologies is introduced.
Abstract: In large-scale data center (DC) and high performance computing (HPC) interconnect networks, end-to-end latency becomes a fatal problem due to the processing and queuing delays of electronic packet switching (EPS) at intermediate switching points. Introducing optical switching into DC and HPC networks can provide a potential solution to the latency problem by establishing low-latency optical bypass (end-to-end lightpath). However, the number of connections that can be provided by current coarse-grained optical circuit switching (OCS) technology is far less than the required amount for all-to-all communication in a hundreds-of-thousands-nodes large-scale system, and this will weaken its effect in reducing latency. Optical packet switching has a much finer granularity compared with OCS; however, the lack of adequate technologies for optical buffering makes it difficult to avoid packet collision. In this paper, we investigate the relationship among network scale, granularity and latency, and introduce the use of our proposed fine-grained optical time slice switching (OTSS) in DC and HPC networks over arbitrary topologies. Simulation results under 6×6 2-D Torus topology demonstrate the advantage of OTSS in end-to-end latency compared with conventional EPS and spectrum-flexible wavelength switching (WS).

Patent
Lu Wei1, Zhou Han1, Qian Tao1
13 Jul 2017
TL;DR: In this paper, a transceiver module of the data packet processing apparatus receives a first data packet; a processing module determines, according to a load status of each VAS instance corresponding to each service chain in a service chain, a service path that the first packet is to go through.
Abstract: The present invention relates to a data packet processing apparatus located in a value-added-service (VAS) network. A transceiver module of the data packet processing apparatus receives a first data packet; a processing module determines, according to a load status of each VAS instance corresponding to each VAS type in a service chain that the first data packet is to go through, a service path that the first data packet is to go through the transceiver module sends the first data packet carrying a service path identifier to a data packet routing apparatus in the network, to instruct the data packet routing apparatus to route the first data packet according to the service path identified by the service path identifier. Load on each VAS instance is considered to avoid that load on devices in a same VAS type is uneven.

Patent
17 Aug 2017
TL;DR: In this article, the authors propose a packet transfer method that requires a terminal apparatus for a physical address corresponding to a logical address of a transmission source of a packet, and determine whether the correspondence relationship between the physical address and the logical address is legal.
Abstract: A packet transfer method includes requesting a terminal apparatus for a physical address corresponding to a logical address of a transmission source of a packet; determining legality of a correspondence relationship between the physical address and the logical address by comparing a physical address indicated by a response from the terminal apparatus with the physical address of the transmission source of the packet; storing a first set of the physical address of the transmission source and the logical address of the transmission source of the packet, when it is determined that the correspondence relationship is legal; when a new packet is received, determining whether a second set of a physical address of a transmission source and a logical address of the transmission source of the new packet coincides with the first set; and transferring the new packet, when it is determined that the second set coincides with the first set.

Patent
25 May 2017
TL;DR: In this paper, a system, method and device for error detection/estimation in OFDM communications systems is proposed, which allows an efficient error prediction in a received packet, without having to perform full FEC decoding of the packet that could impair the overall latency of the system due to the time spent in a complete FEC decoding.
Abstract: A system, method and device for error detection/estimation in OFDM communications systems is proposed. The disclosed mechanism allows an efficient error prediction in a received packet, without having to perform full FEC decoding of the packet that could impair the overall latency of the system due to the time spent in a complete FEC decoding of the packet. In order to do that, it generates a decision variable with the aim to check whether a received packet has errors or not, after performing only partial FEC decoding of the packet, without either resorting to the use of error-detection codes.

Journal ArticleDOI
Wooguil Pak1
TL;DR: This work proposes a new packet classification algorithm that runs fast even with the huge number of policy rules and enjoys both the fast packet classification speed and the short policy update time, making it very suitable for highly dynamic environments like 5G networks.
Abstract: Vehicle-to-everything (V2X) is one of the key applications of upcoming 5G systems. The 5G systems are highly anticipated to adopt software defined network/network function virtualization technology in their core networks as it provides high flexibility and maintainability. However, if the flow tables in switches, called OpenFlow switches, overflow due to excessive policy rules, the networks suffer from large packet delay and frequent packet drops, and fail to support V2X services. To resolve this issue, we propose a new packet classification algorithm that runs fast even with the huge number of policy rules. There is the minimal concern for the overflow in our scheme since it is a pure software-based approach. Furthermore, simulation results show that our algorithm enjoys both the fast packet classification speed and the short policy update time. Thus, our scheme is very suitable for highly dynamic environments like 5G networks.

Journal ArticleDOI
TL;DR: DOWFAF can greatly increase the goodput of large Transmission Control Protocol (TCP) flows for a wide range of traffic, while decreasing the cost and the power consumption.
Abstract: A hybrid optical architecture combining path (circuit) and packet switching can be a good candidate for future optical networks because it exploits the best of both worlds. In this paper, we present a control framework called the Dynamic Optical Wavelength and Flow Allocation Framework (DOWFAF), which can dynamically change the ratio of path and packet wavelengths and the flow size threshold in the hybrid path–packet integrated networks in order to balance the utilization of path and packet subnetworks and maximize the ratio of large flows benefiting from the path switching. We propose an analytical model for calculating the flow size threshold and a feedback control for estimating the wavelength allocation ratio for varying traffic. DOWFAF can be implemented by software-defined networking, which is getting a lot of attention recently. We show that DOWFAF can greatly increase the goodput of large Transmission Control Protocol (TCP) flows for a wide range of traffic, while decreasing the cost and the power consumption.

Proceedings ArticleDOI
01 Jan 2017
TL;DR: Simulation results show that both architectures easily achieve performance targets set by the Metro Ethernet Forum, as long as the network is properly dimensioned.
Abstract: In this paper we assess the performance delivered in a metro network by two optical packet switching architectures, enabling sub-wavelength switching granularity. We compare POADM (Packet Optical Add/Drop Multiplexer) with TWIN (Time-domain Wavelength Interleaved Network). These technologies are envisaged to be deployed in the metropolitan area in order to improve bandwidth utilization and minimize energy consumption, thanks to their excellent switching granularity. In order to perform a realistic performance assessment, the study was carried out over a large set of traffic demands, for which the candidate architectures were first dimensioned taking into account network reliability. Then, the delivered data plane performance was assessed by simulation in terms of electronic packet loss, jitter and insertion delay. Two routing scenarios (any-to-any and hub-and-spoke) are mapped on a physical topology inspired from a European operator network. Simulation results show that both architectures easily achieve performance targets set by the Metro Ethernet Forum, as long as the network is properly dimensioned.

Proceedings ArticleDOI
Xiaoshan Yu1, Huaxi Gu1, Kun Wang1, Meng Xu1, Yantao Guo 
05 Jan 2017
TL;DR: With this scheme, the expensive and energy-hungry elements, optical or electrical buffers, can be removed from the optical interconnects, thus a more scalable and cost-efficient network can be constructed for cloud computing data centers.
Abstract: Optical data center networks are becoming an increasingly promising solution to solve the bottlenecks faced by electrical networks, such as low transmission bandwidth, high wiring complexity, and unaffordable power consumption. However, the optical circuit switching (OCS) network is not flexible enough to carry the traffic burst while the optical packet switching (OPS) network cannot solve the packet contention in an efficient way. To this end, an improved switching strategy named OPS with multi-hop Negative Acknowledgement (MPNACK) is proposed. This scheme uses a feedback mechanism, rather than the buffering structure, to handle the optical packet contention. The collided packet is treated as a NACK packet and sent back to the source server. When the sender receives this NACK packet, it knows a collision happens in the transmission path and a retransmission procedure is triggered. Overall, the OPS-NACK scheme enables a reliable transmission in the buffer-less optical network. Furthermore, with this scheme, the expensive and energy-hungry elements, optical or electrical buffers, can be removed from the optical interconnects, thus a more scalable and cost-efficient network can be constructed for cloud computing data centers.

Patent
Daniel Godas-Lopez1
23 Feb 2017
TL;DR: In this article, the authors present methods and apparatus for packet-based validation of control flow transfers for hardware control-flow enforcement, where a first identifier is determined for a source packet that implements a jump, where the determination is based on a computation using contents within the source packet itself.
Abstract: Disclosed are methods and apparatus for packet based validation of control flow transfers for hardware control-flow enforcement. The methods and apparatus achieve control-flow validation through the determination of a first identifier for a source packet that implements a jump, where the determination is based on a computation using contents within the source packet itself. Similarly, a second identifier is determined for a target packet to which the source packet is directed based on a computation using contents of the target packet. The identifiers may be predetermined based on the packet contents, and may also involve insertion of No Operation instructions to ensure the computations based on the packet contents yield the desired identifiers. The identifiers may then be compared to determine whether they match or are compatible, and an invalid control flow can be detected if they are not compatible.

Patent
05 Jan 2017
TL;DR: In this paper, a method and apparatus for packet communication using header compression is described, which includes applying a header compression protocol to generate a packet to be transmitted, determining whether the packet is dropped in a transport layer, and transmitting a full packet having an uncompressed header.
Abstract: Disclosed are a method and apparatus for packet communication using header compression. The method includes applying a header compression protocol to generate a packet to be transmitted, determining whether the packet is dropped in a transport layer, and transmitting, if it is determined that the packet is dropped, a full packet having an uncompressed header.

Proceedings ArticleDOI
15 May 2017
TL;DR: An approach for a hybrid optical packet switching and optical circuit switching spatial division network using homogeneous single-mode multi-core fibers is described and shown to have potential to achieve acceptable levels of flexibility and granularity suitable for ultra high-capacity spatial division networks.
Abstract: We describe and demonstrate an approach for a hybrid optical packet switching and optical circuit switching spatial division network using homogeneous single-mode multi-core fibers. We show that this approach has potential to achieve acceptable levels of flexibility and granularity suitable for ultra high-capacity spatial division networks.

Proceedings ArticleDOI
01 Jul 2017
TL;DR: This paper discusses a recent ultra-high capacity OPS experimental demonstration, with top switching speed of 12.8 Tb/s/port, that makes use of the aforementioned DCBMRX and electro-optical switching matrices based on (Pb,La)(Zr,La)O3 (PLZT).
Abstract: Optical packet switching (OPS) subsystems have a crucial role in current optical access networks and may be essential in future access and datacenter networks, where the requirements for higher data-rates, transparency, reduced end-to-end latency and optimized energy consumption may be enabled by increasing the network granularity and introducing flexibility on both the line-rate and the modulation format at the optical layer. This paper reviews recent research on two important subsystems of such new generation OPS networks: a digital coherent burst-mode receiver (DCBMRX) for PDM-QPSK and PDM-16QAM modulation formats and a line-rate flexible coherent burst-mode receiver. Finally, we discuss a recent ultra-high capacity OPS experimental demonstration, with top switching speed of 12.8 Tb/s/port, that makes use of the aforementioned DCBMRX and electro-optical switching matrices based on (Pb,La)(Zr,La)O 3 (PLZT). The optical switching control plane is able to resolve packet contention by means of packet buffering and packet discarding.

Journal ArticleDOI
TL;DR: An Adaptive LTE-Advanced cross-layer packet Scheduling (ALS) to guarantee real-time high-speed packet service for LTE- advanced is proposed and numerical results demonstrate ALS outperforms the compared approaches in system capacity, packet dropping probability, average packet delay, etc.
Abstract: In 4G, LTE-Advanced specifies the key objective that the gigabit data rate for real-time video streaming can be transmitted under a high mobility scenario; thus, packet scheduling and radio resource management become the critical techniques that should be addressed effectively. Additionally, the mechanisms of relaying and the OFDMA coding have been certainly adopted in LTE-Advanced and IEEE 802.16 j/m for the purposes of increasing the wireless service coverage and improving signal quality of UEs nearing the cell boundaries. Several studies propose some improvements for the relaying-based packet scheduling, but suffer from long packet delay, high packet dropping probability moderate system capacity, and degrading QoS of real-time packet transmissions. This paper thus proposes an Adaptive LTE-Advanced cross-layer packet Scheduling (ALS) to guarantee real-time high-speed packet service for LTE-Advanced. ALS consists of two mechanisms: (1) Adaptive Reward Priority Scheduling: the cross layer-based adaptive packet scheduling at the MAC layer and (2) Dynamic Resource Allocation algorithm: the efficient radio resource allocation at the PHY layer. Numerical results demonstrate ALS outperforms the compared approaches in system capacity, packet dropping probability, average packet delay, etc.

Proceedings ArticleDOI
01 Apr 2017
TL;DR: In this article, energy consumption of multi-mode routers that support electronic packet switching, optical burst switching and optical circuit switching on the same platform is investigated. And the results show that optical packet switching has the highest energy consumption.
Abstract: An unprecedented growth in the number of internet users has resulted in an increase in power consumption of the network components and auxiliary services. It is widely believed that optical switching technologies have shown great promise in terms of bandwidth offerings and consume far less energy per bit compared to its electronic counterpart. In this paper, we characterize energy consumption of multi-mode routers that support electronic packet switching, optical burst switching and optical circuit switching on the same platform. Two models, namely, Arrayed Waveguide Grating (AWG) and Micro-Electro-Mechanical systems (MEMS), are applied to multi-mode routers. Simulations are performed using the ns-2 tool. Energy consumption per bit of different switching technologies is compared, and results show that optical packet switching has the highest energy consumption. Also the power consumption of AWG optical switches and MEMS optical switch in both blocking and non-blocking modes is compared.

Patent
19 Oct 2017
TL;DR: In this paper, the authors present a method for waking an ONU from an energy-saving mode in a passive optical network in time when a traffic rate at an initial service stage is small, and a high QoS requirement of a service is met.
Abstract: Embodiments of the present invention disclose a method for awaking an optical network unit in a passive optical network, including: receiving, by an optical line terminal OLT, a service packet corresponding to an ONU in an energy-saving mode, where the service packet carries a packet feature, and the packet feature indicates a service type of the service packet; detecting, by the OLT, the packet feature of the service packet; and when the packet feature of the service packet is a preset packet feature of needing to awake the ONU, awaking, by the OLT, the ONU in the energy-saving mode. According to the technical solutions provided in the embodiments of the present invention, an ONU can be awoken from an energy-saving mode in time when a traffic rate at an initial service stage is small, and a high QoS requirement of a service is met.

Journal ArticleDOI
TL;DR: This work investigates a cognitive radio (CR) system where secondary user (SU) relays primary user (PU) packets using two-phase relaying and finds optimal access policy of SU, and proposes low complexity sub-optimal access policies, namely constant probability transmission and step transmission.
Abstract: We investigate a cognitive radio system where secondary user (SU) relays primary user (PU) packets using two-phase relaying. SU transmits its own packets with some access probability in relaying phase using time sharing. PU and SU have queues of finite capacity which results in packet loss when the queues are full. Utilizing knowledge of relay queue state, SU aims to maximize its packet throughput while keeping packet loss probability of PU below a threshold. By exploiting structure of the problem, we formulate it as a linear program and find optimal access policy of SU. We also propose low complexity sub-optimal access policies, namely constant probability transmission and step transmission. Numerical results are presented to compare performance of proposed methods and study effect of queue sizes on packet throughput.