• Cognitive radio aided Vehicular ad-hoc networks with efficient spectrum allocation and QoS guarantee

      Eze, Joy C.; Zhang, Sijing; Liu, Enjie; Theresa, Efor E.; Eze, Elias Chinedum; University of Bedfordshire; Ebonyi State University (Institute of Electrical and Electronics Engineers Inc., 2016-10-24)
      The increasing demand of diverse vehicular network oriented applications (both safety and non-safety related services would undoubtedly lead to shortage of spectral resource challenge for V2V communication networks. In order to resolve this issue, a novel Adaptive CR Enabled Vehicular NETwork (ACREVNET) framework is proposed in this paper. To avoid heavy overhead usually incurred during spectrum sensing, we developed a novel CR adaptive spectrum sensing (CRASS) scheme that can reduce the spectrum sensing cost and improve sensing performance effectively. We also applied the concept of Nash Bargaining Solution (NBS) to guarantee fairness in spectral resources allocation and proposed a generalized non-symmetric NBS (GNNBS) to perform a non-symmetric cognitive inter-cell spectrum allocation in the proposed ACREVNET framework. Simulation results clearly show that the proposed schemes can acquire additional spectral resource for vehicular communication by applying CR technology, and reduce the message transmission delay and blocking probability significantly.
    • Cognitive radio-enabled Internet of Vehicles: a cooperative spectrum sensing and allocation for vehicular communication

      Eze, Joy C.; Zhang, Sijing; Liu, Enjie; Eze, Elias Chinedum; University of Bedfordshire; Ebonyi State University (IET, 2018-02-07)
      Internet of Things (IoTs) era is expected to empower all aspects of Intelligent Transportation System (ITS) to improve transport safety and reduce road accidents. US Federal Communication Commission (FCC) officially allocated 75MHz spectrum in the 5.9GHz band to support vehicular communication which many studies have found insufficient. In this paper, we studied the application of Cognitive Radio (CR) technology to IoVs in order to increase the spectrum resource opportunities available for vehicular communication, especially when the officially allocated 75MHz spectrum in 5.9GHz band is not enough due to high demands as a result of increasing number of connected vehicles as already foreseen in the near era of IoTs. We proposed a novel CR Assisted Vehicular NETwork (CRAVNET) framework which empowers CR enabled vehicles to make opportunistic usage of licensed spectrum bands on the highways. We also developed a novel co-operative three-state spectrum sensing and allocation model which makes CR vehicular secondary units (SUs) aware of additional spectrum resources opportunities on their current and future positions and applies optimal sensing node allocation algorithm to guarantee timely acquisition of the available channels within a limited sensing time. The results of the theoretical analyses and simulation experiments have demonstrated that the proposed model can significantly improve the performance of a cooperative spectrum sensing and provide vehicles with additional spectrum opportunities without harmful interference against the Primary Users (PUs) activities.
    • RECMAC: reliable and efficient cooperative cross-layer MAC scheme for vehicular communication based on random network coding technique

      Eze, Elias Chinedum; Zhang, Sijing; Liu, Enjie; Nweso, Emmanuel N.; Eze, Joy C.; University of Bedfordshire; Ebonyi State University (Institute of Electrical and Electronics Engineers Inc., 2016-10-24)
      In an unreliable cluster-based, broadcast-oriented vehicular network setting, we investigate the transmission reliability and throughput performance of random network coding (RNC) as a function of the packet generate rate. Our proposed model consists of a source vehicle broadcasting packets to a set of receivers (i.e. one-to-many) over independent broadcast erasure channels. The source vehicle performs RNC on N packets and broadcasts the encoded message to a set of receivers. In each hop, several vehicles form a cluster and cooperatively transmit the encoded or re-encoded packet. The combination of RNC, cluster based, and cooperative communications enables RECMAC to optimally minimize data redundancy, which means less overhead, and improve reliability as opposed to existing coding-based solutions. Theoretic analyses and simulation results show that RECMAC scheme can achieve optimal performance in terms of transmission reliability and throughput.
    • Reliable and enhanced cooperative cross-layer medium access control scheme for vehicular communication

      Eze, Elias Chinedum; Zhang, Sijing; Liu, Enjie; Eze, Joy C.; Muhammad, Shehu Jabaka; University of Bedfordshire; Ebonyi State University; Federal College of Education (Technical) Gusau (IET, 2018-04-05)
      In an unreliable cluster-based, broadcast vehicular network setting, we investigate the transmission reliability and throughput performance of random network coding (RNC) as a function of the percentage of packet generation rate and transmit power to noise ratio. In the paper, a novel scheme called reliable and efficient cooperative cross-layer MAC (RECMAC) is proposed. The proposed scheme consists of a source vehicle broadcasting packets to a set of receivers (i.e. one-to-many) over independent broadcast erasure channels. The source vehicle performs RNC on N packets and broadcasts the encoded message to a set of receivers. In each hop, several vehicles form a cluster and cooperatively transmit the encoded or re-encoded packet. The combination of RNC, cluster based, and cooperative communications enables RECMAC to optimally minimize data redundancy, which means less overhead, and improve reliability as opposed to coding-based solutions. Theoretical analyses and simulation results show that under the same conditions RECMAC scheme can achieve improved performance in terms of transmission reliability and throughput.
    • Spectrum requirement for efficient wireless communication over vehicular networks∗

      Eze, Elias Chinedum; Eze, Joy C.; Zhang, Sijing; Liu, Enjie; Ebonyi State University; University of Bedfordshire (Institute of Electrical and Electronics Engineers Inc., 2019-07-01)
      This paper studied the required amount of radio spectral resource enough to support timely and reliable vehicular communication via vehicular ad-hoc networks (VANETs). The study focused on both DSRC/WAVE and the European standard ITS-G5 that are based on recently approved IEEE 802.11p specification, which uses a simplified version of CSMA/CA as MAC protocol, and an STDMA MAC recently proposed by European Telecommunications Standards Institute (ETSI). The paper further carried out a feasibility analysis of radio spectrum requirement for timely and reliable vehicle-to-vehicle (V2V) communication. In the feasibility analysis, synchronized STDMA MAC is compared with the CSMA/CA MAC protocol, which 802.11p is based on. Message Reception Failure (MRF) probability is used as a performance metric to investigate and ascertain the minimum spectrum requirement for efficient, timely, and reliable V2V communication. Simulation results show that even at the same allocation of 10MHz channel bandwidth, STDMA MAC outperforms the CSMA/CA based MACs due to the fact that STDMA based MACs provide a structured shared medium access and prevent negative impact of unhealthy contention for shared channel access. The results further show that up to 40MHz channel bandwidth over 5.9GHz band would be required to guarantee optimal reliability of safety packets exchange in vehicular networks as opposed to 10MHz allocated in US.