Loss Diagnosis and Indoor Position Location System based on IEEE 802.11 WLANs

Wireless local area networks (WLANs) have been widely deployed to provide short range broadband communications. Due to the fast evolvement of IEEE 802.11 based WLAN standards and various relevant applications, many research efforts have been focused on the optimization of WLAN data rate, power and channel utilization efficiency. On the other hand, many emerging applications based on WLANs have been introduced. Indoor position location (IPL) system is one of such applications which turns IEEE 802.11 from a wireless communications infrastructure into a position location network. This thesis mainly focuses on data transmission rate enhancement techniques and the development of IEEE 802.11 WLAN based IPL system with improved locationing accuracy. In IEEE 802.11 systems, rate adaptation algorithms (RAAs) are employed to improve transmission efficiency by choosing an appropriate modulation and coding scheme accord­ ing to point-to-point channel conditions. However, due to the resource-sharing nature of WLANs, co-channel interferences and frame collisions cannot be avoided, which further complicates the wireless environment and makes the RAA design a more challenging task. As WLAN performance depends on many dynamic factors such as multipath fading and co-channel interferences, differentiating the cause of performance degradation such as frame losses, which is known as loss diagnosis techniques, is essential for performance enhance­ ments of existing rate adaptation schemes. In this thesis, we propose a fast and reliable collision detection scheme for frame loss diagnosis in IEEE 802.11 WLANs. Collisions are detected by tracking changes of the signal-to-interference-and-noise-ratio (SINR) in IEEE 802.11 WLANs with a nonparametric order-based cumulative sum (CUSUM) algorithm for rapid loss diagnosis. Numerical simulations are conducted to evaluate the effectiveness of the proposed collision detection scheme. The other aspect of this thesis is the investigation of an IEEE 802.11 WLAN based IPL system. WLAN based IPL systems have received increasing attentions due to their variety of potential applications. Instead of relying on dedicated locationing networks and devices, IEEE 802.11 WLAN based IPL systems utilize widely deployed IEEE 802.11 WLAN infrastructures and standardized wireless stations to determine the position of a target station in indoor environments. iii Abstract In this thesis, a WLAN protocol-based distance measurement technique is investigated, which takes advantages of existing IEEE 802.11 data/ACK frame exchange sequences. In the proposed distance measurement technique, neither dedicated hardware nor hardware modifications is required. Thus it can be easily integrated into off-the-shelf commercial, inexpensive WLAN stations for IPL system implementation. Field test results confirm the efficacy of the proposed protocol-based distance measurement technique. Furthermore, a preliminary IPL system based on the proposed method is also developed to evaluate the feasibility of the proposed technique in realistic indoor wireless environments

Evaluation on Rate Adaptation Algorithm Applied For Wireless Mesh Network

 Penelitian ini mengevaluasi beberapa algoritma rate adaptation untuk mendapatkan algoritma yang paling sesuai digunakan pada jaringan wireless mesh network (WMN). Pada beberapa penelitian terdahulu, evaluasi terhadap algoritma-algoritma rate adaptation masih terbatas pada kinerja algoritma rate adaptation secara umum dan pada jaringan yang sederhana, sedangkan untuk penelitian ini dikhususkan pada kenaikan nilai throughput yang disebabkan oleh penerapan algoritma rate adaptation dan pada jaringan yang lebih kompleks yaitu WMN. Algoritma rate adaptation yang dipilih untuk dievaluasi adalah algoritma-algoritma yang sudah umum digunakan, yaitu algoritma auto rate fallback (ARF), adaptive auto rate fallback (AARF) dan collision aware rate adaptation (CARA). Evaluasi dilakukan melalui serangkaian simulasi menggunakan software NS-3 untuk mengetahui nilai throughput yang dihasilkan oleh masing-masing algoritma pada kondisi jaringan WMN dengan jumlah node yang berbeda-beda. Hasil evaluasi menunjukkan bahwa kinerja algoritma CARA mampu melampaui kinerja dua algoritma lainnya, yaitu ARF dan AARF untuk kondisi jaringan WMN yang kompleks (grid 4x5 dan 5x5).This paper attempts to evaluate some rate adaptation algorithms in order to find the most suitable algorithm to be used in the wireless mesh network (WMN) environment. In some previous researches, the evaluation on these algorithms is still limited on a general rate algorithm performance and in a simple network, while this research was devoted on the increase in throughput value due to the implementation of rate adaptation algorithm and in a more complicated network, WMN. The rate adaptation algorithms evaluated in this research were auto rate fallback (ARF), adaptive auto rate fallback (AARF) and collision aware rate adaptation (CARA), which are the most commonly used algorithm. The evaluation was carried out through a series of simulation using NS-3 software to find out the throughput value resulted by each algorithm. The evaluation result showed that the CARA algorithm outperformed two other algorithms, i.e. ARF and AARF, for a complex WMN condition (grid 4x5 and 5x5).Keywords: Jaringan WMN, throughput, rate adaptation algorithm, CARA, NS-3ReferensiCapone, A. Carello, G. 2006. Scheduling optimization in wireless mesh networks with power control and rate adaptation. In  Sensor and Ad Hoc Communications and Networks, 2006. SECON'06. 2006 3rd Annual IEEE Communications Society on, (Vol. 1, pp. 138-147). IEEE.     Senthilkumar, D. Krishnan, A. 2010. Throughput analysis of IEEE 802.11 multirate WLANs with collision aware rate adaptation algorithm. International Journal of Automation and Computing, 7(4), 571-577.Lacage, M., Manshaei, M. H., Turletti, T. 2004, October. IEEE 802.11 rate adaptation: a practical approach. In Proceedings of the 7th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems (pp. 126-134). ACM.Kim, J., Kim, S., Choi, S., Qiao, D. 2006, April. CARA: Collision-Aware Rate Adaptation for IEEE 802.11 WLANs. In INFOCOM (Vol. 6, pp. 1-11)

Evaluation on Rate Adaptation Algorithm Applied For Wireless Mesh Network

Penelitian ini mengevaluasi beberapa algoritma rate adaptation untuk mendapatkan algoritma yang paling sesuai digunakan pada jaringan wireless mesh network (WMN). Pada beberapa penelitian terdahulu, evaluasi terhadap algoritma-algoritma rate adaptation masih terbatas pada kinerja algoritma rate adaptation secara umum dan pada jaringan yang sederhana, sedangkan untuk penelitian ini dikhususkan pada kenaikan nilai throughput yang disebabkan oleh penerapan algoritma rate adaptation dan pada jaringan yang lebih kompleks yaitu WMN. Algoritma rate adaptation yang dipilih untuk dievaluasi adalah algoritma-algoritma yang sudah umum digunakan, yaitu algoritma auto rate fallback (ARF), adaptive auto rate fallback (AARF) dan collision aware rate adaptation (CARA). Evaluasi dilakukan melalui serangkaian simulasi menggunakan software NS-3 untuk mengetahui nilai throughput yang dihasilkan oleh masing-masing algoritma pada kondisi jaringan WMN dengan jumlah node yang berbeda-beda. Hasil evaluasi menunjukkan bahwa kinerja algoritma CARA mampu melampaui kinerja dua algoritma lainnya, yaitu ARF dan AARF untuk kondisi jaringan WMN yang kompleks (grid 4x5 dan 5x5). This paper attempts to evaluate some rate adaptation algorithms in order to find the most suitable algorithm to be used in the wireless mesh network (WMN) environment. In some previous researches, the evaluation on these algorithms is still limited on a general rate algorithm performance and in a simple network, while this research was devoted on the increase in throughput value due to the implementation of rate adaptation algorithm and in a more complicated network, WMN. The rate adaptation algorithms evaluated in this research were auto rate fallback (ARF), adaptive auto rate fallback (AARF) and collision aware rate adaptation (CARA), which are the most commonly used algorithm. The evaluation was carried out through a series of simulation using NS-3 software to find out the throughput value resulted by each algorithm. The evaluation result showed that the CARA algorithm outperformed two other algorithms, i.e. ARF and AARF, for a complex WMN condition (grid 4x5 and 5x5). Keywords: Jaringan WMN, throughput, rate adaptation algorithm, CARA, NS-3 Referensi Capone, A. & Carello, G. 2006. Scheduling optimization in wireless mesh networks with power control and rate adaptation. In  Sensor and Ad Hoc Communications and Networks, 2006. SECON'06. 2006 3rd Annual IEEE Communications Society on, (Vol. 1, pp. 138-147). IEEE.      Senthilkumar, D. & Krishnan, A. 2010. Throughput analysis of IEEE 802.11 multirate WLANs with collision aware rate adaptation algorithm. International Journal of Automation and Computing, 7(4), 571-577. Lacage, M., Manshaei, M. H., & Turletti, T. 2004, October. IEEE 802.11 rate adaptation: a practical approach. In Proceedings of the 7th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems (pp. 126-134). ACM. Kim, J., Kim, S., Choi, S., & Qiao, D. 2006, April. CARA: Collision-Aware Rate Adaptation for IEEE 802.11 WLANs. In INFOCOM (Vol. 6, pp. 1-11)

Experimental Study on the Performance of Rate Adaptation Algorithm in IEEE 802.11g Networks

IEEE 802.11 technology provides a low-cost wireless networking solution. In the last few years, we have seen that the demand for high-bandwidth wireless local area networks increases rapidly, due to the proliferation of mobile devices such as laptops, smart phones and tablet PCs. This has driven the widespread deployment of IEEE 802.11 wireless networks to provide Internet access. However, wireless networks present their own unique problems. Wireless channel is extremely variable and can be affected by a number of different factors, such as collisions, multipath fading and signal attenuation. As such, rate adaptation algorithm is a key component of IEEE 802.11 standard which is used to vary the transmission data rate to match the wireless channel conditions, in order to achieve the best possible performance. Rate adaptation algorithm studies and evaluations are always hot research topics. However, despite its popularity, little work has been done on evaluating the performance of rate adaptation algorithms by comparing the throughput of the algorithm with the throughput of the fixed rates. This thesis presents an experimental study that compares the performance ofMikroTik rate adaptation algorithm andMinstrel rate adaptation algorithm against fixed rates in an IEEE 802.11g network. MikroTik and Minstrel rate adaptation algorithm are most commonly used algorithm around the world. All experiments are conducted in a real world environment in this thesis. In a real world environment, wireless channel conditions are not tightly being controlled, and it is extremely vulnerable to interference of surrounding environment. The dynamic changes of wireless channel conditions have a considerable effect on the performance of rate adaptation algorithms. The main challenge of evaluating a rate adaptation algorithm in a real world environment is getting different experiment behaviours from the same experiment. Experiment results may indicate many different behaviours which due to the leak of wireless environment controlling. Having a final conclusion from those experiment results can be a challenge task. In order to perform a comprehensive rate adaptation algorithm evaluation. All experiments run 20 times for 60 seconds. The average result and stand deviation is calculated. We also design and implement an automation experiment controlling program to help us maintain that each run of experiment is following exactly the same procedures. In MikroTik rate adaptation algorithm evaluation, the results show in many cases that fixed rate outperforms rate adaptation. Our findings raise questions regarding the suitability of the adopted rate adaptation algorithm in typical indoor environments. Furthermore, our study indicates that it is not wise to simply ignore fixed rate. A fine selection of a fixed rate could be made to achieve desired performance. The result ofMinstrel rate adaptation evaluation show that whilst Minstrel performs reasonably well in static wireless channel conditions, in some cases the algorithm has difficulty selecting the optimal data rate in the presence of dynamic channel conditions. In addition, Minstrel performs well when the channel condition improves frombad quality to good quality. However, Minstrel has trouble selecting the optimal rate when the channel condition deteriorates from good quality to bad quality. By comparing the experimental results between the performance of rate adaptation algorithms and the performance of fixed data rate against different factors, the experiment results directly pointed out the weakness of these two rate adaptation algorithms. Our findings from both experiments provide useful information on the design of rate adaptation algorithms