Optical orthogonal frequency division multiplexing (OFDM) is regarded as a promising modulation technique for next-generation PON, owing to the advantages in high spectrum efficiency, cost-effectiveness, and tolerance to fiber dispersion. Moreover, due to flexible digital signal processing (DSP) in electric domain, digital chaos is easier to be applied.
Because it offers very appealing properties from the perspective of data encryption such as ergodicity, pseudo-randomness, and high sensitivity to the initial values, digital chaos provides a huge key space for security applications. On the other hand, digital chaos has attracted notable attention recently as a flexible alternative to avoid the implementation difficulty for device-based optical chaos. However, the implementation of chaotic optical communication (i.e., fast changing of chaotic optical carriers) requires identical devices with identical parameters for transmitter and receiver, which is quite restricted from real implementation.
For security reasons, churning procedure of scrambling the data for downstream connection has been defined in ITU-T G.983.1 standard (Section 8.3.5.6 ), which is based on a key sent from ONU to OLT through a secure channel with a defined protocol however, the key is vulnerable to be broken due to its limited short key length.Ĭhaos communication has been proposed to provide a huge key space for data security enhancement attributed to its unpredictable nature of randomness, noise-like nature, and broadband. If the physical-layer data encryption is implemented, this type of spoofing can be avoided since the header and ID information are all encrypted within the physical-layer thus, it becomes desirable for security enhancement in PON.
TRANSMISSION FOR MAC SETTINGS PIA 2017 SERIAL NUMBER
For instance, during the ranging process, the OLT has to broadcast the serial number and ID information of the ranged ONUs a malicious user could make use of this information for spoofing.Ĭomparing with the encryption in higher layers, for instance, media access control (MAC) layer, physical-layer encryption can protect the data as well as the control and header information. The broadcasting nature in the downstream data traffic and the huge number of subscribers in PON make the data more susceptible to be eavesdropped or attacked by illegal ONUs. In fact, PON is a broadcasting structure that extends for ~20–100 km from optical line terminal (OLT) to optical network units (ONUs), in which no active component (such as Erbium-doped fiber amplifier, EDFA) is employed. Over the last decades, passive optical network (PON) has been playing a vital role in data traffic explosion driven by broadband services such as high-definition television (HDTV), cloud computing, 3D television, video on demand (VoD), and so on, because it offers several potential benefits such as high capacity, low cost, and energy efficiency. The chaotic data encryption schemes could be promising candidates for next-generation OFDM-PON. The evidences of these encryption approaches are presented in terms of theories, simulations, as well as experimental demonstrations. Multi-fold data encryption is achieved with a huge key space provided by digital chaos, to enhance the physical-layer security for OFDM-PON, while the pseudo-random properties of digital chaos are applied for PAPR reduction, which consequently improves the transmission performance. The digital chaos is incorporated into the signal scrambling approaches: selective mapping (SLM), partial transmit sequence (PTS) and precoding approaches: discrete Fourier transform (DFT) and Walsh-Hadamard transform (WHT) for PAPR reduction. This chapter reviews the digital chaos-based secure OFDM data encryption schemes, where the transmission performance is improved via PAPR reduction. For the transmission of orthogonal frequency division multiplexing (OFDM) signals, the high peak-to-average power ratio (PAPR) is considered as one of the major drawbacks. Due to the broadcasting nature of passive optical network (PON), data security is challenging.
0 kommentar(er)
