Spectral amplitude coding OCDMA using and subtraction technique

Abstract

An optical decoding technique is proposed for a spectral-amplitude-coding-optical code division multiple access, namely, the AND subtraction technique. The theory is being elaborated and experimental results have been done by comparing a double-weight code against the existing code, Hadamard. We have proved that the and subtraction technique gives better bit error rate performance than the conventional complementary subtraction technique against the received power level.

Modelling and simulation of a 1.6 Tb/s optical system based on multi-diagonal code and optical code-division multiple-acces

“…(23) has been employed to calculate the BER for the MD code. To ensure fair performance comparison for the MD-code system, the present study uses the same parameters as adopted in the earlier works [10][11][12][13][14][15][16][17]. Table 2 lists the parameters chosen in the calculations for the MD and the other SAC-OCDMA codes.…”

“…Spectral amplitude coding for the optical code-division multiple-access (SAC-OCDMA) system offers a good solution that reduces the MAI effect by utilising codes with a fixed in-phase cross-correlation [9]. A lot of codes have been suggested for the SAC-OCDMA networks (an optical orthogonal (OOC) code [10], a prime code [11], a Khazani-Syed (KS) code [12], an enhanced double weight (EDW) code [13], a modified frequency-hopping (MFH) code [14], a modified quadratic congruence (MQC) code [15], a random diagonal (RD) code [16], a modified double weight (MDW) code [17], etc.). These codes suffer from several limitations: the code length is often too long (e.g., for the OOC, KS and the EDW codes), the code construction is limited by the code parameter (e.g., for the MQC and MFH codes), whereas the cross-correlation usually increases with increasing weight number (e.g., for the prime code and the RD code).…”

“…These codes suffer from several limitations: the code length is often too long (e.g., for the OOC, KS and the EDW codes), the code construction is limited by the code parameter (e.g., for the MQC and MFH codes), whereas the cross-correlation usually increases with increasing weight number (e.g., for the prime code and the RD code). In addition, the codes suggested in the works [10][11][12][13][14][15][16][17] cannot support large enough numbers of simultaneous users or high data rates. To overcome these problems, we have suggested a so-called multidiagonal (MD) code.…”

Enhancement of performance of a hybrid SAC-OCDMA system using dynamic cyclic shift code

“…Many different codes have been considered for the SAC-OCDMA networks. These include, in particular, an optical orthogonal code [9], a prime code [10], a Khazani-Syed (KS) code [11], an enhanced double weight (EDW) code [12], a modified frequency hopping (MFH) code [13], a modified quadratic congruence (MQC) code [14], a random diagonal (RD) code [15], and a modified double weight (MDW) code [16]. However, all of these codes suffer from some limitations.…”

Improving spectral efficiency of SAC-OCDMA systems by SPD scheme

“…Recently, the authors proposed the modified-AND subtraction detection technique to reduce PIIN and MAI in incoherent SAC-OCDMA systems by dividing the spectrum of the decoded signals [2]. The modified-AND subtraction detection technique has the same receiver complexity as the AND detection technique [3], but offers enhanced system performance. Both of these techniques use balanced detection, composed of two photodiodes connected electrically in opposition, where the output signal is proportional to the power difference between the two optical inputs.…”