Optimization of resources for H.323 endpoints and terminals over VoIP networks
- Authors: Nlend, Samuel , Swart, Theo G. , Clarke, Willem A.
- Date: 2011
- Subjects: VoIP Networks , Statistical multiplexing , Telecommunications
- Language: English
- Type: Conference paper
- Identifier: http://hdl.handle.net/10210/139763 , uj:15455 , S. Nlend, T. G. Swart and W. A. Clarke, "Optimization of resources for H.323 endpoints and terminals over VoIP networks," in Proceedings IEEE Africon, Livingstone, Zambia, September 13-15, 2011, published on CD (5 pages)
- Description: We suggest a method of optimizing resource allocation for real time protocol traffic in general, and VoIP in particular, within an H.323 environment. There are two options in the packet network to allocate resources: aggregate peak demand and statistical multiplexing. Statistical multiplexing, our choice for this case, allows the efficient use of the network resources but however exhibits greater packet delay variation and packet transfer delay. These delays are often the result of correlations or time dependency experienced by the system’s queue due to the variations observed in different point processes that occur at a point of time. To address these issues, we suggest a queuing method based on the diffusion process approximated by Orstein-Ulenbeck and the non-validated results of Ren and Kobayashi.
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Optimization of resources for H.323 endpoints and terminals over VoIP networks
- Authors: Nlend, Samuel , Swart, Theo G. , Clarke, Willem A.
- Date: 2011
- Subjects: H.323 endpoints , VoIP networks
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/18245 , uj:15976 , ISBN: 978-1-61284-993-5 , Citation: Nlend, S., Swart, T.G. & Clarke, W.A. 2011. Optimization of resources for H.323 endpoints and terminals over VoIP networks. Proceedings IEEE Africon, 13-15 September, Livingstone, Zambia.
- Description: Abstract: We suggest a method of optimizing resource allocation for real time protocol traffic in general, and VoIP in particular, within an H.323 environment. There are two options in the packet network to allocate resources: aggregate peak demand and statistical multiplexing. Statistical multiplexing, our choice for this case, allows the efficient use of the network resources but however exhibits greater packet delay variation and packet transfer delay. These delays are often the result of correlations or time dependency experienced by the system’s queue due to the variations observed in different point processes that occur at a point of time. To address these issues, we suggest a queuing method based on the diffusion process approximated by Orstein-Ulenbeck and the non-validated results of Ren and Kobayashi.
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Optimization of resources allocation for H.323 endpoints and terminals over VoIP networks
- Authors: Nlend, Samuel
- Date: 2014-01-27
- Subjects: Internet telephony , TCP/IP (Computer network protocol) , Broadband communication systems
- Type: Thesis
- Identifier: uj:7960 , http://hdl.handle.net/10210/8860
- Description: M.Phil. (Electrical & Electronic Engineering) , Without any doubt, the entire range of voice and TV signals will migrate to the packet network. The universal addressable mode of Internet protocol (IP) and the interfacing framing structure of Ethernet are the main reasons behind the success of TCP/IP and Ethernet as a packet network and network access scheme mechanisms. Unfortunately, the success of the Internet has been the problem for real-time traffic such as voice, leading to more studies in the domain of Teletraffic Engineering; and the lack of a resource reservation mechanism in Ethernet, which constitutes a huge problem as switching system mechanism, have raised enough challenges for such a migration. In that context, ITU-T has released a series of Recommendation under the umbrella of H.323 to guarantee the required Quality of Service (QoS) for such services. Although the “utilisation” is not a good parameter in terms of traffic and QoS, we are here in proposing a multiplexing scheme with a queuing solution that takes into account the positive correlations of the packet arrival process experienced at the multiplexer input with the aim to optimize the utilisation of the buffer and bandwidth on the one hand; and the ITU-T H.323 Endpoints and Terminals configuration that can sustain such a multiplexing scheme on the other hand. We take into account the solution of the models from the M/M/1 up to G/G/1 queues based on Kolmogorov’s analysis as our solution to provide a better justification of our approach. This solution, the Diffusion approximation, is the limit of the Fluid process that has not been used enough as queuing solution in the domain of networking. Driven by the results of the Fluid method, and the resulting Gaussian distribution from the Diffusion approximation, the application of the asymptotic properties of the Maximum Likelihood Estimation (MLE) as the central limit theorem allowed capturing the fluctuations and therefore filtering out the positive correlations in the queue system. This has resulted in a queue system able to serve 1 erlang (100% of transmission link capacity) of traffic intensity without any extra delay and a queue length which is 60% of buffer utilization when compared to the ordinary Poisson queue length.
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An access optimization approach for FFH-OCDMA system’s fiber bragg gratings encoder
- Authors: Nlend, Samuel , Swart, Theo G. , Twala, Bhekisipho
- Date: 2017
- Subjects: Bragg gratings , FFH-OCDMA , Multiaccess communication
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/243869 , uj:25211 , Citation: Nlend, S., Swart, T.G. & Twala, B. 2017. An access optimization approach for FFH-OCDMA system’s fiber bragg gratings encoder.
- Description: Abstract: This paper suggests an adaptive 2-D Optical CDMA coding system based on one-coincidence frequency hopping (OCFH) code combined with an optical orthogonal code (OOC) in the format OCFH/OOC, suitable for the fast frequency hopping optical code division multiple access (FFH-OCDMA) channel, encoded by the Bragg gratings encoder with an aim to optimize the access network in terms of number of users and transmitted power. As wavelength hopping (WH) code, the OCFH code is herein adapted to the constraints of the encoder: the Bragg gratings chain put on the optical fiber...
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Study of the US road network based on social network analysis
- Authors: Mambou, Elie Ngomseu , Nlend, Samuel , Liu, Harold
- Date: 2017
- Subjects: Social network analysis (SNA) , Community structure , Spark
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/248044 , uj:25777 , Citation: Mambou, E.N., Nlend, S. & Liu, H. 2017. Study of the US road network based on social network analysis.
- Description: Abstract: The complexity of big data structures and networks demands more research in terms of analysing and representing data for a better comprehension and usage. In this regard, there are several types of model to represent a structure. The aim of this article is to use a social network topology to analyse road network for the following States in the United States (US): California, Pennsylvania and Texas. Our approach mainly focuses on clustering of road network data in order to create “communities”.
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Enhanced 3-D OCDMA code family using asymmetric run length constraints
- Authors: Nlend, Samuel , Swart, Theo G
- Date: 2019
- Subjects: Optical orthogonal code (OOC) , Optical code division multiple access (OCDMA) , Difference of position (DoP)
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/406708 , uj:34205 , Citation: Nlend, S., Swart, T.G. 2019 : Enhanced 3-D OCDMA code family using asymmetric run length constraints.
- Description: Abstract : This paper suggests an enhanced performance of the 3-D optical code division multiple access (OCDMA) codes, a space/wavelength/time spreading family of codes. The initial codes are in the format wavelength hopping/time sequence (WH/TS), selected according to their performance requirements and the TS sequence is constructed to achieve a linear space- time complexity. The asymmetric run length constraints are introduced in that regard, such that the positive bit positions align with the encoder/decoder frequency spacing pattern, yielding a 3-D WH/WS/TS. The selected 2-D OCDMA codes are one- coincidence frequency hopping codes (OCFHC) and optical orthogonal codes (OOC). As a time sequence code, the OOC code length is extended with a code rate of 0.04. The complexity and the bit error rate (BER) are herein given and compared with previous work. The results of the performance show not only an improvement in the number of simultaneous users due to the code length extension, but better correlation properties and hence a better signal-to-noise ratio.
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Enhancing the performance of FFH-OCDMA channels with combined access, line and error correcting codes
- Authors: Nlend, Samuel
- Date: 2019
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/499966 , uj:45701
- Description: D.Phil. (Electric and Electronic Engineering) , Abstract: Please refer to full text to view abstract.
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