Joint Link Scheduling and Routing for Load Balancing in STDMA Wireless Mesh Networks

In wireless mesh networks, it is known to be effective to use a TDMA based MAC than a contention-based CSMA. In addition, if spatial TDMA is used, network performance can be improved further because of its spatial reuse effect. However this scheme still has a disadvantage in the system performance aspect without a load-balanced routing because the resource of links that are not used is wasted and frequently used links are out of resources. That is, the number of available flows in network is limited because load balancing is not performed. In this paper, we propose joint link scheduling and routing through a cross-layer scheme. For this, we propose a load balancing routing method to maximize available resources under the given traffic pattern and scheduling method for maximizing link utilization on the given route. These two methods are iterated until an optimized solution can be obtained. The proposed algorithm can be formulated using a mathematical LP problem and we show that it is very effective for load balancing compared to simple adoption of IEEE 802.11s which is a standard TDMA protocol in wireless mesh network. If the proposed algorithm is applied to initial design solution such as Smart Grid, the number of available flows can be increased and the load on each link can be balanced

802.11s QoS Routing for Telemedicine Service

The merits of 802.11s as the wireless mesh network standard provide a lowcost and high independent scalability telemedicine infrastructure. However,challenges in degradation of performance as hops increase and the absent of Quality of Service (QoS) provision need to be resolved. The reliability and timely manner are the important factor for successful telemedicine service. This research investigates the use of 802.11s for telemedicine services. A new model of 802.11s based telemedicine infrastructure has been developed for this purpose. A non deterministic polynomial path selection is proposed to provide end-to-end QoS provisioning in 802.11s. A multi-metric called QoS Price metric is proposed as measurement of link quality. The QoS Price is derived from multi layers values that reflect telemedicine traffic requirement and the resource availability of the network. The proposed solution has modified the path management of 802.11s and added resource allocation in distributed scheme.DOI:http://dx.doi.org/10.11591/ijece.v4i2.559

Integration of multimetric path management into 802.11S for telemedicine quality of service provision

The merits of 802.11s as the wireless mesh network standard provide a low cost and high independent scalability telemedicine infrastructure. However, challenges in degradation of performance as hops increase and the absence of Quality of Service (QoS) provision need to be resolved. Reliability and timely manner are important factors for successful telemedicine service. This research investigates the use of 802.11s for telemedicine services. A new model of 802.11s based on telemedicine infrastructure has been developed for this purpose. A non deterministic polynomial path selection is proposed to provide end-to-end QoS provisioning in 802.11s. A multi-metric called QoS Price metric is proposed as measurement of link quality. The QoS Price is derived from multi layers values that reflect telemedicine traffic requirement and resource availability of the network. The proposed solution has modified the path management of 802.11s and added resource allocation in distributed scheme. This modification and resource allocation improvement of 802.11s were given the designation medQoS-802.11s. MedQoS- 802.11s could provide a link guarantee of telemedicine traffic transmission in the selected path. MedQoS-802.11s had been tested using ns3 simulation and real environment testbed. The result has shown that medQoS-802.11s could achieve the traffic guarantee for almost 95% telemedicine traffic with 58% for the resource intensive diagnostic video traffic. It has also shown that the cost of link path overhead is efficient with the transmission overhead having an increment of 6% compared to the original 802.11s. The concurrent connection results for single time transmission shows that medQoS-802.11s has a significant increase of up to 12% traffic than original 802.11s. The testbed results have verified the QoS guarantee of the intended telemedicine traffic per transmission time. In summary, the reliability and time guarantee of medQoS has highly improved 802.11s to transmit telemedicine traffic

A Novel Packet Aggregation Mechanism for Enhancing VoIP Performance on IEEE 802.11 Wireless Mesh Networks

In 802.11 Wireless Mesh Network (WMN), bandwidth will be wasted much for transferring VoIP flows since each voice frame must contain relatively large amount of protocol data. “Packet Aggregation” mechanism can be applied to merge the voice data of multiple VoIP flows into one frame for transmission. It reduces the waste on bandwidth and increases the maximum number of successful VoIP calls. In addition, the mechanism “MCF controlled channel access” (MCCA) defined in 802.11 standard can be used to obtain better QoS than adopting default EDCA mechanism. In MCCA, mesh stations which wants to transfer VoIP flows can reserve time intervals of the medium for transmission and this reservation will be advertised to their neighbors. It is why MCCA causes less medium contentions than EDCA. In this paper, a mechanism to transfer VoIP flows in IEEE 802.11 WMN by MCCA with packet aggregation scheme is proposed. The effectiveness of the proposed mechanism is shown by simulation results. In addition, the problem named as Routing-Packet Aggregation / De-aggregation-Scheduling optimization problem (abbr. RPADS problem) derived from the proposed mechanism is also studied. A heuristic algorithm for RPADS problem to maximize the total number of supported calls is also proposed

Layer 2 Path Selection Protocol for Wireless Mesh Networks with Smart Antennas

In this thesis the possibilities of smart antenna systems in wireless mesh networks are examined. With respect to the individual smart antenna tradeoffs, a routing protocol (Modified HWMP, MHWMP) for IEEE 802.11s mesh networks is presented, that exploits the full range of benefits provided by smart antennas: MHWMP actively switches between the PHY-layer transmission/reception modes (multiplexing, beamforming and diversity) according to the wireless channel conditions. Spatial multiplexing and beamforming are used for unicast data transmissions, while antenna diversity is employed for efficient broadcasts. To adapt to the directional channel environment and to take full benefit of the PHY capabilities, a respective MAC scheme is employed. The presented protocol is tested in extensive simulation and the results are examined.:1 Introduction 2 Wireless Mesh Networks 3 IEEE 802.11s 4 Smart Antenna Concepts 5 State of the Art: Wireless Mesh Networks with Smart Antennas 6 New Concepts 7 System Model 8 Results and Discussion 9 Conclusion and Future Wor