The coexistence needs of sensing and communication in millimeter-wave (mmW) bands have urgently driven the seamless integration of sensing and communication in the upcoming mmW era. However, the time-frequency competition between the two functions makes it difficult to accommodate both high sensing resolution and large communication capacity. In this paper, we have designed a W-band fiber-wireless link with the integrated sensing and communication functions enabled by electromagnetic polarization multiplexing. The ultra-wideband fiber-wireless link in W band is enabled by the asymmetrical single-sideband modulation along with the optical heterodyne up-conversion. The electromagnetic polarization multiplexing allocates the sensing and communication functions on two orthogonal electromagnetic polarizations, respectively. Thus, all time-frequency resources of the fiber-wireless link can simultaneously serve these two functions without any resource competition, contributing to an ultra-high spatial resolution and an ultra-large data capacity at the same time. Our experimental results show the spatial resolution of up to 15 mm and data rate as high as 92 Gbit/s were simultaneously realized in W band after delivering over a 10.8-m wireless distance. The overall improvement of both the sensing and communication performance, to the best of our knowledge, led to a record capacity-resolution quotient of 61.333 Gbit/s/cm. In addition, we have qualitatively investigated the integrated sensing and communication fiber-wireless link, in terms of the carrier frequency, system bandwidth, multi-mmW access, and electromagnetic polarization crosstalk.

As the mobile communication evolves from sub-6GHz to millimeter wave (MMW) frequency bands, the demand for high-speed wireless transmission rates exceeding hundreds of gigabits per second is becoming more and more prominent. It is one of the important cornerstones supporting numerous emerging bandwidth-consuming applications represented by the metaverse, digital twin and so on. So far, there is a huge room for improvement in wireless transmission rate, which is far inferior to the transmission capacity of fiber optic links. In this paper, we have proposed and experimentally demonstrated a large-capacity photonics-assisted MMW wireless communication system over 20-km fiber and 1.3-m wireless transmission at the W band. A dual-polarized single-input single-output (SISO) wireless link, instead of the commonly used 2×2 multiple-input multiple-output (MIMO) links, is used for the transparent transmission of optical polarization division multiplexing signal, which significantly simplifies the system complexity and enhances its robustness. In addition, the transmission performance is further improved by employing an advanced MIMO Volterra nonlinear equalizer. With the bit error ratio threshold of 2×10-2, a record single-lane single-carrier wireless air interface rate (WAIR/ch/λ) up to 504 Gb/s has been achieved for the first time. This solution we proposed provides opportunity for progress in the wireless air interface capacity close to the fiber-optic transmission capacity in the fiber-wireless integration transmission systems.

In fiber-wireless integration systems, it is valuable to investigate whether digital subcarrier multiplexing (SCM) signal is effective in improving nonlinear tolerance against photodiode (PD) saturation compared to single-carrier (SC) signal. For a fair comparison, the mitigation of linear impairments especially for IQ mixing effects become significant. In this article, we first analyze the impacts of transmitter IQ mixing effects for SC and digital SCM signals. Then, we employ the real-valued multiple-input multiple-output (MIMO) post-equalizers for the PM (polarization multiplexing)-SC system and PM-SCM system so as to mitigate transmitter IQ mixing effects. Finally, we experimentally compare the nonlinear tolerance of SC, SCM with two subcarriers (SCM-2), and SCM-4 signals using QPSK, 8QAM, and 16QAM in a W-band fiber-wireless system against the pin-photodiode (PIN-PD) saturation considering noise-limited case, optimum case and non-linear case. Subcarriers for SC, SCM-2, and SCM-4 are 25GBaud, 12.5GBaud, and 6.25GBaud respectively, with a total symbol rate of 25GBaud. Maximum line rate is 200 Gb/s with the BER satisfying the 7% HD-FEC threshold when employing the PM-16QAM. The results show that SCM signal has better nonlinear tolerance against the PIN-PD saturation than SC signals when system works in the non-linear case especially when using high-order modulation formats.

Intensity modulation/direct detection (IM/DD) and coherent schemes are two kinds of promising solutions to achieve the evolution for B5G/6G fronthaul networks. IM/DD has more mature commercial deployment applications for short-reach applications with lower costs and simpler configurations compared with coherent solutions. In this paper, we experimentally demonstrate a local area network-wavelength division multiplexing (LAN-WDM) IM/DD access system with a record bit rate of 2 Tb/s (250 Gbit/s×8) probabilistic shaping eight-pulse amplitude modulation (PS-PAM-8) signal with joint equalization techniques to support the evolution of future B5G/6G mobile fronthaul networks. Considering the 20% Soft Decision Forward Error Correction (SD-FEC) threshold with the bit error rate (BER) of 2×10 ^-2 , we realize a record net bit rate of 1.6 Tb/s over 5 km fiber. This system can potentially support a 12-wavelengths transmission with the total line rate of 3 Tb/s (250 Gbit/s×12). Moreover, we analyze the challenges of the evolution, usage scenarios, digital signal processing (DSP) implementation, transmission rate and distance, and the tolerance of dispersion with different wavelengths. The LAN-WDM can be considered as a feasible and potential candidate scheme to meet the evolution and deployment of B5G/6G Terabit/s fronthaul networks.

To relieve network resource pressure and avoid network congestion, the adoption of a sliding scheduling traffic model is crucial to achieve flexible radio access network (RAN) function deployment and provide customized services. In this paper, we investigate the problem of dynamic RAN slicing mapping under the sliding scheduled traffic model in metro-access/aggregation elastic optical networks (EONs). These particular sliding scheduled RAN slicing requests allow for an initial latency during the setup phase, as long as resource allocation is available prior to a preset deadline. To combine RAN slicing request scheduling in the time domain with routing and spectrum assignment (RSA) in the spectrum domain, we propose a dynamic RAN slicing mapping (DRSM) algorithm for EONs based on deep reinforcement learning (DRL). In our DRSM method, we introduce a time-frozen scheme aimed at reducing the action space to accelerate the training process. Simulation results on a 30-node network topology demonstrate that the proposed DRL-based DRSM method outperforms the two baseline heuristics, potentially saving at least 48.1% more blocking probability under the sliding scheduled traffic model with different arrival rates and sliding factors.