Link Asymmetry in Virtual MISO-based Networks

2013 ◽  
Author(s):  
Haejoon Jung ◽  
Mary Ann Weitnauer
Keyword(s):  
Link Asymmetry

scholarly journals Minimizing the Adverse Effects of Asymmetric Links: A Novel Cooperative Asynchronous MAC Protocol for Wireless Sensor Networks

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2402 ◽  
Author(s):  
Md. Mahedee Hasan ◽  
Amit Karmaker ◽  
Mohammad Shah Alam ◽  
Andrew Craig
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Cooperative Communication ◽  
Mac Protocol ◽  
Research Work ◽  
Wireless Sensor ◽  
Medium Access ◽  
Link Asymmetry ◽  
Asymmetric Link ◽  
Asymmetric Links

As Wireless Sensor Networks (WSNs) grow in popularity, researchers are now focusing more on some challenging issues that significantly degrade overall performance, such as energy hole mitigation, link asymmetry minimization, etc. Link asymmetry is a problem that arises when the coverage distance between two adjacent nodes varies. It creates an obstacle to overcome when designing an efficient Medium Access Control (MAC) protocol for WSNs with low duty-cycling. This phenomenon poses an especially difficult challenge for receiver-initiated asynchronous MAC protocols, which are popular due to their relatively higher energy efficiency. Exploiting the benefits of cooperative communication has emerged as one of the viable solutions to overcome this limitation. Cooperative communication in WSNs has received a lot of attention in recent years. Many researchers have worked to create a MAC layer supporting cooperative communication. However, the association of cooperative communication with an asymmetric link is not studied in the literature. In this research work, COASYM-MAC, a cooperative asynchronous MAC protocol for WSNs, is proposed based on a receiver-initiated MAC protocol that uses the fact that nodes have alternate paths between them to reduce link asymmetry. A key feature of the proposed protocol is that the optimal helper node is selected automatically in case of link asymmetry. Simulations exhibited that COASYM-MAC performs significantly better than a state-of-the-art MAC protocol for WSNs that handles asymmetric links, ASYM-MAC.

An Extended Cross Layer Approach Handling Asymmetry with Quality of Service, Congestion Avoidance and Congestion Aware Routing

2018 ◽  
Vol 15 (2) ◽  
pp. 676-684 ◽  
Author(s):  
N. Yuvaraj ◽  
P. Thangaraj
Keyword(s):  
Quality Of Service ◽  
Congestion Control ◽  
Mesh Networks ◽  
Network Capacity ◽  
Congestion Avoidance ◽  
Cross Layer ◽  
The Cross ◽  
Link Asymmetry ◽  
Congestion Aware

Nodes in wireless multi-hop networks establish links with their neighbors that are used for data transmission. In Wireless Mesh Networks (WMNs) working in an ad hoc model, a transmission region of mesh routers and mesh clients is heterogeneous which cause link asymmetry. The cross-layer framework was developed to handle link asymmetry problems such as unidirectional link issue, heterogeneous exposed problem and heterogeneous hidden problem. Additionally, congestion control and quality of service (QoS) requirements are required to enhance the performance of network. Hence, in this paper, the Cross Layer approach Handling Link Asymmetry (CHLA) is extended as quality-of-service aware routing (CHLA-QSAR) and quality-of-service with congestion control aware routing (CHLA-QSCCAR). QoS requirements are achieved by Signal strength estimation, network capacity estimation, MAC scheduling, Link Scheduling and Slot assignment. Congestion is controlled by a proposed bandwidth management mechanism by congestion window management dependent on the dynamic incidents of traffic conditions. Moreover, congestion avoidance mechanism is also proposed with Quality of Service with Congestion aware routing (QSCACAR). The simulation is conducted for CHLA, CHLA-QSAR, and CHLA-QSCCAR and CHLA-QSCACAR methods in terms of bit error rate, end to end delay, latency, routing overheads and throughput. The simulation results proved that each proposed work is consecutively improving the performance than CHLA.

A Cross-Layer Approach Handling Link Asymmetry for Wireless Mesh Access Networks

2011 ◽  
Vol 60 (3) ◽  
pp. 1045-1058 ◽  
Author(s):  
Yuefeng Huang ◽  
Xinyu Yang ◽  
Shuseng Yang ◽  
Wei Yu ◽  
Xinwen Fu
Keyword(s):  
Access Networks ◽  
Cross Layer ◽  
Wireless Mesh ◽  
Link Asymmetry
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