|
| Year | Author and reference details | Proposed opportunistic routing framework | Metric used for evaluating performance | Bullet points | Future research directions |
|
| 2010 | Eu et al. [122] | EHOR | Fairness, hop count, efficiency, data delivery ratio, goodput, throughput, and source sending rate | (i) An opportunistic routing framework is proposed with consideration of energy constraints for multihop EH-WSNs. | (i) As future work, the proposed framework can be used for a 2D topology.
(ii) Next, future work includes the use of network coding for enhancement of performance. |
|
| 2012 | Eu and Tan [123] | AOR | Throughput and fairness | (i) An adaptive opportunistic routing framework is proposed for multihop EH-WSNs.
(ii) The proposed framework provides a higher throughput.
(iii) The proposed framework utilized the regioning scheme and also capable enough to change as per conditions of network and energy profiles. | (i) Future research directions may consider the work towards addressing factors that are not addressed in this framework.
(ii) The cost of multihop transmission is affected by the duty cycle of relay nodes and it results in the selection of inappropriate routes. |
|
| 2013 | Beheshtiha et al. [124] | OR-AhaD | Hop count, data delivery ratio, goodput, and efficiency | (i) An opportunistic routing framework is presented with a duty cycle approach having awareness of adaptive harvesting mechanism.
(ii) The proposed framework utilized the geographical zoning approach for prioritizing the candidates set.
(iii) The model is presented for managing the energy, and in this model, the duty cycle is adaptively adjusted based on the estimation of harvesting rate in the future. | (i) Future research directions may consider the work towards consideration of the effect of prediction accuracy in the performance of the routing framework.
(ii) Next, future research directions may consider the work for the requirement of the unified evaluation framework for comparing the existing solutions.
(iii) Further, future research directions may consider the work towards test-bedding the existing routing frameworks for exploring the implementation issues. |
|
| 2017 | Shafieirad et al. [125] | Max-SNR | Data delivery ratio and transmitted messages per node | (i) A novel opportunistic routing framework is presented for multihop large-scale EH-WSNs with energy awareness.
(ii) The proposed scheme considered the three factors while selecting the next forwarder such as energy profile, distance, and also the amount of data. | (i) Future research directions may consider the work towards addressing factors that are not addressed in this framework.
(ii) The proposed scheme may result in packet loss as well as poor delay in the case of heterogeneous and dynamic duty cycle and consequently selecting the sleeping relay nodes for packet transmission.
(iii) The duty cycle cannot be adjusted accurately and this results in the limited performance of EH-WSNs. |
|
| 2018 | Zhang et al. [126] | OPEH | Delivery ratio and delay | (i) A novel opportunistic packet forwarding framework is presented with consideration of heterogeneous and dynamic duty cycle.
(ii) The echo state network is utilized for adjusting the duty cycle. | (i) Future research directions may consider the work towards enhancing the efficiency of the echo state network since it is utilized in the current work for adjusting the duty cycle. |
|
| 2019 | Cheng et al.[127] | ORDTP | Packet redundancy ratio, delay, and delivery ratio | (i) An opportunistic routing framework is presented with consideration of dynamic transmission power for EH-WSNs.
(ii) The salient features of the proposed framework include collecting the information about neighbor nodes and estimation of the transmission cost accurately.
(iii) In the proposed framework, the priorities, members, and size are dynamically updated. | (i) Further, future research directions may consider the work towards test-bedding the existing routing framework for exploring the performance in actual deployment with implementation issues. |
|
| 2020 | Rathore et al. [128] | OOR | Delay, packet delivery ratio, and throughput | (i) An optimal opportunistic routing framework is presented with consideration of a dynamic duty cycle based on the modified echo state network for EH-WSNs.
(ii) In the proposed framework, the whale optimization algorithm is used for enhancing the prediction efficiency of the echo state network. | (i) Further, future research directions may consider the work towards test-bedding the existing routing framework for exploring the performance in actual deployment with implementation issues. |
|
| 2020 | Singh and Pattanayak [129] | MEHOR | Efficiency, throughput, goodput, source sending rate, data delivery ratio, and hop counts | (i) An opportunistic routing framework is presented with consideration of cross-layer design.
(ii) The proposed framework utilized the Markovian model for cross-layer design. | (i) Further, future research directions may consider the work towards key challenges in the proposed framework such as reducing the duplicate packets. |
|
