Fresh Prime Codes Evaluation for Synchronous PPM and OPPM Signaling for Optical CDMA Networks

Karbassian, M. Massoud; Ghafouri‐Shiraz, H.

doi:10.1109/jlt.2007.896809

Cited by 40 publications

(33 citation statements)

References 7 publications

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“…Other members include the new Modified Prime code and the Double padded modified prime code proposed by Karbassian and Shiraz [9]. They are also unipolar sequences, they can be used in On-OFF Keying (OOK) and in pulse position modulation (PPM).…”

Section: Prime Code Familymentioning

confidence: 99%

Transmission scheduling in optical CDMA networks using hybridized overlap and threshold (HOT) scheduling algorithm

2015

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The bane of optical network is multiuser interference as a result of codewords overlap from different nodes simultaneously transmitting. Transmission scheduling is a good interference avoidance scheme which helps prevent throughput degradation at high offered load in an optical code division multiple access local area network. Interference avoidance consists of state estimation and transmission scheduling. This work examines different scheduling algorithms and parameter variations. This work investigated the performance of three scheduling algorithms (Pure Selfish Scheduling, Threshold Scheduling and Overlap Section Scheduling) against the ALOHA CDMA and our novel Hybrid-Hybridized Overlap and Threshold Scheduling-HOT algorithms using the modified padded prime codeset. The performance of the scheduling algorithms are measured in terms of its normalized network throughput, packet error rate and the average number of codewords allow into the line against the normalized offered load. The analysis shows that under this condition, the Hybridized Overlap-Threshold scheduling perform best and has throughputs as high as the 52 % with nearly zero packet error rate while the nonscheduled algorithm produce a throughput as low as 10 % and very high error rate at maximum offered load. Overall, the Threshold Scheduling and HOT algorithm are head to head B 'Ladi Ogunwolu and performed best in terms of normalized network throughput, however the HOT scheduling is best in terms of the packet error rate. Analysis also shows that the throughput is not affected by changes in codeset length and the mean packet size but it is affected by changes in the codeset weight. The study also analyzes the performance of the network under a bimodal packet distribution and with the Prime code codeset family. Optical Orthogonal Codeset and the Prime codeset family are used in the study under the assumption of perfect state estimation; that all nodes have the same view of the network and the transmission lines and the distance between the nodes and the central star coupler is assumed to be zero. A novel hybrid Scheduling Algorithm, the HOT Scheduling which proved better than traditional Scheduling Algorithms is peddled here.

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Section: Prime Code Familymentioning

confidence: 99%

Transmission scheduling in optical CDMA networks using hybridized overlap and threshold (HOT) scheduling algorithm

2015

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“…Hence, several simultaneous transmissions addressed to different receivers are made possible. Because the periodic crosscorrelation between DPMPC sequences in different groups is not zero (but it is as low as '1') (Karbassian and Ghafouri-Shiraz 2007b), the interfering signals will reduce the noise margin of the receivers.…”

Section: Structure Of Coherent Heterodyne Ocdmamentioning

confidence: 99%

“…The code-length and weight of each code become (P 2 + 2P) and (P + 2) respectively. The in-phase correlation function (C mn ) for any pair of codes m and n at synchronization time (T ) is given by Karbassian and Ghafouri-Shiraz (2007b):…”

mentioning

confidence: 99%

Evaluation of coherent homodyne and heterodyne optical CDMA structures

Karbassian

Ghafouri‐Shiraz

2008

Opt Quant Electron

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This paper evaluates the coherent optical code-division multiple-access (OCDMA) techniques and examines the overall system performance in terms of signalto-noise ratio (SNR) penalty as a function of simultaneous users accommodated to maintain an appropriate value of the bit-error rate (BER) for homodyne and heterodyne detections. As spreading codes, the proposed structures are utilizing a recently introduced prime code family hereby referred to as double-padded modified prime code (DPMPC). As a coherent modulation, binary phase-shift keying (BPSK) format is deployed. In homodyne detection, two different phase modulations are studied including either an external phase-modulator or injection-locking methods. The phase limitation and the performance for two methods plus multiple-access interferences (MAI) and receiver noise in a shot-noise limited regime are investigated. In heterodyne detection, BER analysis of the system based on only external phase modulator is examined. It is found that by maintaining BER = 10 −9 , this system can accommodate an increased number of simultaneous users to compare with systems which employ conventional bipolar codes.

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“…Gold codes); it has also been extensively explained and applied to incoherent OCDMA in [6]. The results include the presence of the shot-noise, the distribution of the interferers with the case of periodic cross-correlation of the sequences (synchronous OCDMA).…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Novel Prime Code Family in Coherent Optical CDMA Network

Karbassian¹,

Liu²,

Ghafouri‐Shiraz³

2007

2007 Second International Conference on Communications and Networking in China

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A novel prime code, hereby referred to as 'DoublePadded Modified Prime Code', is introduced and employed in a coherent optical code-division multiple-access (OCDMA). We have analyzed this system signal-to-noise ratio (SNR) penalty as a function of the number of simultaneous users incurred to maintain an appropriate value of the bit-error rate (BER). As a coherent modulation the binary phase-shift keying (BPSK) is analyzed and finally signals are heterodyne-detected and processed at the receiver end. Also, in the analysis both the receiver noise and multiple access interference (MAI) are investigated.

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Fresh Prime Codes Evaluation for Synchronous PPM and OPPM Signaling for Optical CDMA Networks

Cited by 40 publications

References 7 publications

Transmission scheduling in optical CDMA networks using hybridized overlap and threshold (HOT) scheduling algorithm

Transmission scheduling in optical CDMA networks using hybridized overlap and threshold (HOT) scheduling algorithm

Evaluation of coherent homodyne and heterodyne optical CDMA structures

Performance Analysis of Novel Prime Code Family in Coherent Optical CDMA Network

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