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In order to meet the ever-increasing traffic demands, the combination of fiber and Millimeter Wave (mmWave) is expected to play a key role for 5G Centralized-Radio Access Networks (C-RANs). Due to the inefficiency of the Common Public Radio Interface for the Baseband Unit (BBU)-Remote Radio Head (RRH) communication, analog-Radio-over-Fiber (a-RoF) technology is considered a promising solution, mainly due to the RRH simplification and lower fronthaul requirements it imposes. In such mmWave a-RoF C-RANs, efficient Medium Transparent-Medium Access Control (MT-MAC) protocols are needed able to meet the challenging 5G requirements. To this end, in this paper, we propose a gated service MT-MAC protocol which authorizes each user to transmit the amount of data it requested. A detailed delay model is proposed, which is validated through simulations for different fiber lengths, network load conditions and number of available optical wavelengths. Moreover, the proposed protocol is compared with the state-of-the-art (SoA) and is shown to achieve up to 20 times higher throughput, 2 times lower delay with 100% lower blocking probability and 5 times higher data wavelength utilization, while being able to adapt to varying network traffic conditions. Our proposal also attains sub-ms latency in most cases, constituting it a promising candidate for next generation mmWave a-RoF C-RANs.
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... Although CW-MT-MAC was able to achieve fairness among the network users, it still did not consider the actual traffic load of each RAU, as an RAU with more users could in total have lower aggregate traffic load than an RAU with few users being heavily loaded. Motivated by the need for a per-packet-based optical/wireless resource allocation, a trafficaware MT-MAC scheme, termed gated-MT-MAC (gMT-MAC), was recently proposed [20], which employed the gated service paradigm for establishing the SF duration so as to maximize the network performance and spectrum efficiency. The gMT-MAC protocol, where each active user is authorized to transmit in an SF the amount of data it reports at the end of the previous SF, was shown to greatly outperform the original MT-MAC [12], as well as the CW-MT-MAC protocols [19] and achieve up to 20-times higher throughput, 2-times lower delay, and 5-times higher data wavelength utilization. ...
... The above combinations signify that Layer-2 protocols employed in the future FiWi RAN transport networks must support Backhaul/Midhaul and Fronthaul connections, while concurrently meeting their distinct bandwidth, latency, and jitter Key Performance Indicators (KPIs). The gated service regime implemented in the State-of-the-Art (SoA) gMT-MAC protocol [20] does not offer service classification or a way to prioritize packets within the SF, and hence, packet flows originating from X-Haul equipment are served identically; to this end, the gMT-MAC protocol cannot effectively accommodate multiple traffic classes featuring their aforementioned diverse bandwidth, latency, and jitter specifications. To this end, this paper proposes the QoS-aware MT-MAC (qMT-MAC) protocol, which is specifically designed to provide the necessary performance guarantees to the various flows that are expected to traverse the next-generation 5G and beyond transport networks, offering QoS support for three X-Haul traffic classes: (i) low-layer split Fronthaul (FH) traffic that produces Constant Bit Rate (CBR) loads and carries strict delay and jitter requirements, (ii) low-layer split FH that produces load-dependent traffic that carries strict delay requirements, and (iii) higher-layer split traffic that produces load-dependent traffic with more relaxed service constraints in terms of delay. ...
... Section 3.1 summarizes the general operational rules of the SoA MT-MAC protocols presented in [12,19,20] that are in direct relation to the medium arbitration process, using The Ethernet-based communication between the MNO equipment and FiWi qMT-MAC network facilitates the use of enhanced Common Public Radio Interface (eCPRI) messages for data exchange as the predominant protocol for X-Haul communication. In order to encompass and simulate the main eCPRI splits in our study, we considered that the MNO equipment produces the following three types of payloads: ...
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... The seamless integration of wired fiber backhaul and wireless fronthaul is the key issue. Surrounding this issue, the energy-efficient frame aggregation [5], throughput optimization [6], and medium access control (MAC) protocol design [7] were conducted. These three works focused on the improvement of the FiWi network's performance, neglecting the uniqueness of the tactile internet. ...
... To demonstrate the variation in the latencies of multiple hop numbers, [1,7,15] With the growth in the data rate of each tactile service, the latencies of different situations always increases. The control group has the largest values. ...
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... In the shunting stage, the traffic is classified efficiently by extracting the time characteristics of the data and introducing the time characteristics of stack bidirectional long short-term memory learning. There are also many algorithms for traffic control of network resource allocation through TE, and these algorithms have been successfully applied to practical applications [26][27][28][29]. ...
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