Generalized diversity coding is a promising proactive recovery scheme against single edge failures for unicast connections in transport networks. At the source node, the user data is split into two parts, and their bi...
详细信息
Generalized diversity coding is a promising proactive recovery scheme against single edge failures for unicast connections in transport networks. At the source node, the user data is split into two parts, and their bitwise XOR is computed as a third redundancy sub-flow. In order to guarantee instantaneous failure recovery without costly node upgrades, the network must ensure that any two of the three sub-flows reach the destination node in case of a single edge failure only by allowing flow duplication or merging identical flows, and avoiding any coding operation in the core network. In this paper, we investigate the corresponding routing problem to calculate capacity-efficient routes for these sub-flows. We propose a polynomial-time algorithm for topologies without capacity constraints on the links and without capability limitations of the nodes. We show that with node limitations the presented algorithm (as well as a minimum cost disjoint path-pair) provides a 4/3-approximation for the routing problem. Furthermore, we formulate an integer linear program to provide a minimum cost solution with arbitrary constraints in general graphs and we propose a polynomial-time algorithm in directed acyclic graphs. Our simulation results suggest that with upgrading only a small set of core network nodes with flow duplication and merging capabilities most of the benefits of generalized diversity coding can be achieved.
Millimeter Wave systems face significant challenges for robust signal transmission in the presence of aggregated path loss and penetration losses. Namely, once the link between the mobile and base stations is successf...
详细信息
ISBN:
(纸本)9781538675687
Millimeter Wave systems face significant challenges for robust signal transmission in the presence of aggregated path loss and penetration losses. Namely, once the link between the mobile and base stations is successfully established, i.e., based upon initial access schemes that determine the optimum beamforming and combing vectors at which the optimum signal level is detected. However, the signal associated with the optimum link can rapidly degrade due to increased obstacles in the link of various densities and sizes. This yields in reduced signal levels and link failure, consequently resulting in communication loss during control-or user-planes. This paper presents efficient link recovery scheme based upon diversity coding for multi-beam transmissions to overcome blockage effects. The proposed scheme features near-instantaneous link recovery times without the need for repeated beam search over all spatial directions, as compared to traditional recovery schemes that perform exhaustive and iterative beam to determine the new optimum direction.
In this paper, we propose a new proactive recovery scheme against single edge failures for unicast connections in transport networks. The new scheme is a generalization of diversity coding where the source data AB are...
详细信息
In this paper, we propose a new proactive recovery scheme against single edge failures for unicast connections in transport networks. The new scheme is a generalization of diversity coding where the source data AB are split into two parts A and B and three data flows A, B, and their exclusive OR (XOR) A circle plus B are sent along the network between the source and the destination node of the connection. By ensuring that two data flows out of the three always operate even if a single edge fails, the source data can be instantaneously recovered at the destination node. In contrast with diversity coding, we do not require the three data flows to be routed along three disjoint paths;however, in our scheme, a data flow is allowed to split into two parallel segments and later merge back. Thus, our generalized diversity coding (GDC) scheme can be used in sparse but still two-connected network topologies. Our proof improves an earlier result of network coding, by using purely graph theoretical tool set instead of algebraic argument. In particular, we show that when the source data are divided into two parts, robust intra-session network coding against single edge failures is always possible without any in-network algebraic operation. We present linear-time robust code construction algorithms for this practical special case in minimal coding graphs. We further characterize this question, and show that by increasing the number of edge failures and source data parts, we lose these desired properties.
Survivable routing with instantaneous recovery gained much attention in the last decade, as in optical backbone networks even the shortest disruption of a connection may cause tremendous loss of data. Recently, strict...
详细信息
Survivable routing with instantaneous recovery gained much attention in the last decade, as in optical backbone networks even the shortest disruption of a connection may cause tremendous loss of data. Recently, strict delay requirements emerge with the growing volume of multimedia and video streaming applications, which have to be ensured both before and after a failure. diversity coding provides a nice trade-off between the simplicity of dedicated protection and bandwidth-efficiency of network coding to ensure instantaneous recovery for the connections. Hence, in this paper we thoroughly investigate the optimal structure of diversity coding-based survivable routing, which has a well-defined acyclic structure of subsequent paths and disjoint path-pairs between the communication end-points. We define the delay of these directed acyclic graphs, and investigate the effect of Quality-of-Service and differential delay bounds on the solution cost. Complexity analysis and integer linear programs are provided to solve these delay aware survivable routing problems. We discuss their approximability and provide some heuristic algorithms, too. Thorough experiments are conducted to demonstrate the benefits of diversity coding on randomly generated and real-world optical topologies. (C) 2016 Elsevier B.V. All rights reserved.
This paper presents a robust solution for link and node failures in network function virtualization for 5G and beyond system. Namely, the synergistic combination of diversity and Network coding schemes is leveraged he...
详细信息
ISBN:
(纸本)9781538612675
This paper presents a robust solution for link and node failures in network function virtualization for 5G and beyond system. Namely, the synergistic combination of diversity and Network coding schemes is leveraged here for robust link failure recovery. The scheme offers near-instantaneous packet recovery without feedback requests with enhanced throughput. Hence, it eliminates latency associated with retransmissions and rerouting by using error control across spatially diverse paths.
In this paper we study the application of diversity coding to enable near-instantaneous recovery from link failures in 5G Centralized Radio Access Network (C-RAN) networks. We focus on networks where remote radio head...
详细信息
ISBN:
(纸本)9781509043750
In this paper we study the application of diversity coding to enable near-instantaneous recovery from link failures in 5G Centralized Radio Access Network (C-RAN) networks. We focus on networks where remote radio heads in a C-RAN are connected to the baseband unit with wireless fronthaul links. In order to avoid retransmissions and rerouting delays due to link failures, we investigate use diversity coding where a feedforward network design uses forward error control across spatially diverse paths to enable reliable networking with minimal delay.
In distributed multilevel diversity coding, K correlated sources (each with K components) are encoded in a distributed manner such that, given the outputs from any alpha encoders, the decoder can reconstruct the first...
详细信息
In distributed multilevel diversity coding, K correlated sources (each with K components) are encoded in a distributed manner such that, given the outputs from any alpha encoders, the decoder can reconstruct the first alpha components of each of the corresponding alpha sources. For this problem, the optimality of a multilayer Slepian-Wolf coding scheme based on binning and superposition is established when K <= 3. The same conclusion is shown to hold for general K under a certain symmetry condition, which generalizes a celebrated result by Yeung and Zhang.
Survivable routing methods have been thoroughly investigated in the past decades in transport networks. However, the proposed approaches suffered either from slow recovery time, poor bandwidth utilization, high comput...
详细信息
ISBN:
(纸本)9783901882685
Survivable routing methods have been thoroughly investigated in the past decades in transport networks. However, the proposed approaches suffered either from slow recovery time, poor bandwidth utilization, high computational or operational complexity, and could not really provide an alternative to the widely deployed single edge failure resilient dedicated 1 + 1 protection approach. diversity coding is a candidate to overcome these difficulties with a relatively simple technique: dividing the connection data into two parts, and adding some redundancy at the source node. However, a missing link to make diversity coding a real alternative to 1 + 1 in transport networks is finding its minimum cost survivable routing, even in sparse topologies, where previous approaches may fail. In this paper we propose a polynomial-time algorithm with O (vertical bar V vertical bar vertical bar E vertical bar log vertical bar V vertical bar) complexity for this routing problem. On the other hand, we show that the same routing problem turns to be NP-hard as soon as we limit the forwarding capabilities of some nodes and the capacities of some links of the network.
Opportunistic network coding (ONC) increases communication networks' throughput by XORing two or more packets together. However, it has shown that ONC deteriorates in terms of bit error rate (BER) and throughput w...
详细信息
Opportunistic network coding (ONC) increases communication networks' throughput by XORing two or more packets together. However, it has shown that ONC deteriorates in terms of bit error rate (BER) and throughput when deployed in noisy wireless networks. Therefore, we propose a mechanism that combines ONC, diversity coding, and cooperation to mitigate the shortcomings of ONC. Additionally, to reduce delay and error propagation at relay nodes, we limit the maximum number of packets that can be network-coded together to three and only encode packets received directly by relay nodes. Moreover, we study the effect of link outages/mobility and show how to mitigate at least one link failure. Finally, we show that our system alleviates the issues previously mentioned and provides better performance to direct transmission and ONC when implemented in noisy networks using simulations.
In the paper we consider a communication network that uses diversity coding in order to achieve reliability. Having a set of demands and a network topology we face a problem of optimal routing of the demands and backu...
详细信息
暂无评论