1. WiMAX Wi-Fi Wi-Fi (AP) Wi-Fi 1 1 AP AP WLAN [1] [1] [1] WLAN [4] WLAN WLAN WLAN 1 WLAN WLAN WLAN N =3 [1] W

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1 [] LAN NEC 一般社団法人 電子情報通信学会 信学技報 THE INSTITUTE OF ELECTRONICS, IEICE Technical Report INFORMATION AND COMMUNICATION ENGINEERS ASN (216-5) (WLAN) WLAN WLAN WLAN WLAN IEEE 82.11, LAN Throughput characteristics Analysis of Wireless LANs considering Inter-network Interference Takumi AOKI, Kosuke SANADA, Nobuyoshi KOMURO, Gen MOTOYOSHI, Norio YAMAGAKI, Shigeo SHIODA, Shiro SAKATA, Tsutomu MURASE, and Hiroo SEKIYA Graduate School of Advanced Integration Science, Chiba University 1-33, Yayoi-cho, Inage-ku, Chiba, Japan Graduate School of Engineering, Mie University 1577, Kurimamachiya-cho, Tsu-shi, Mie, Japan Cloud System Research Laboratories, NEC Corpration 1753 Shimonumabe, Nakahara-ku, Kawasaki, Japan Information Technology Center, Nagoya University Furo-cho, Chikusa-ku, Nagoya, Japan Abstract Recently, the environment where there are many Access-Points(AP) in a small area exists everywhere. In this environment, network throughput of certain WLAN reduces significantly because of inter-network interference. This manuscript presents analitycal expressions of network throughputs for wireless LANs with airtime concepts taking into account inter-network interference. each network throughput can be obtained analytically by expressing frame collision probability and frame-existence probabilities with respect to each node. The validities of the analytical explessions are confirmed from quantitative agreements between analytical and simulation results. Key words IEEE 82.11, throughput analysis, inter-network, interference, WLAN 75 This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere. Copyright 216 by IEICE

2 1. WiMAX Wi-Fi Wi-Fi (AP) Wi-Fi 1 1 AP AP WLAN [1] [1] [1] WLAN [4] WLAN WLAN WLAN 1 WLAN WLAN WLAN N =3 [1] WLAN Network 1 Network 2 Network N 1 3 WLAN 2. 2 [1] 1 [4] [4]- [7] WLAN 76

3 UDP 2. WLAN i [, T ime] i X i = lim T ime S i T ime S i i (DIFS + F RAME + SIFS + ACK) DIFS DIFS(DCF InterFrame Space) F RAME SIFS SIFS(Short InterFrame Space) ACK ACK (1) i E i = Xi(1 γi)p T γ i i T P 3. 2 i i Y i = X i 1(1 γ i 1,i)+X i+1(1 γ i+1,i) Xi 1(1 γi 1,i)Xi+1(1 γi+1,i) (3) 1 X i γ j,i j i X i γ j,i = γ i,j i i 1 i (1) (2) Z i =1 X i Y i (4) 3. 4 i i 1 ( q i =min 1, λ ) iv i σ (5) Z i σ V i i λ i i λ i = Oi P O i i q i < 1 i q i =1 i min 3. 5 [8] i K G i = Ri V i = γi s s= K γi s W s 2 s= R i i 1 2 s (CW min +1) 1 < = s < = K 1 W s = 2 K (CW min +1) 1=CW max K < = s < = K CW min CW max Contention Window K = log 2 CW max +1 CW min +1 K (5) (7) i (6) (7) (8) τ i = q ig i (9) 1 X i = q iz i G i T σ (1) σ q i Z i i (4) (1) 2 77

4 3. 6 i i ± 1 U j,i U i,i±1 = Z i±1 1 X i±1 X i(1 γ i,i±1) (11) WLAN 2 N 1 1 N 2 N 1 1 N j i γ j,i j i i i τ i (j =2,i=1or j = N 1,i= N) γ j,i = (12) U j,i τ i (otherwise) τ i i (12) γ i =1 (1 γ i,j ) (13) j=i+1 j=i 1 j =i (3) (4) (5) (7) (12) (1) X i N 4. 1 N =3, 4 N =3 1 N = (a), 4(b) Mbps 2 1 Data payload 15 bytes PHY header 24 bytes MAC header 24 bytes ACK size 1 bytes Data rate 54 Mbps ACK bit rate 24 Mbps DATA 252 μs DIFS 34 μs SIFS 16 μs Slot time(σ) 9 μs CW min 15 CW max 123 Retry limit(k) 7 Inter-network distance 3 m Transmission range 45 m Carrier sense range 45 m 1 2(c) 13.3 Mbps ,2 4(c) 4(d) Mbps N =4 5(a), 5(b) 13.2 Mbps (c) (c) 5(d) Mbps Mbps Mbps

5 3 4(c) LAN LAN [1],,,,,,,,,, Wi-Fi Wi-Fi, 215, 216. [2] Minh Huy Bui, Kokuse Sanada, Nobuyoshi Komuro, Shigeo Shioda, Shiro Sakata, Kazunori Miyoshi, Tutomu Murase and Hiroo Sekiya, Throughput analysis of wireless networks with Tethering function, IEEE Wireless communications and networking conference (WCNC215), pp , Mar [3],,,,,,,,,, vol.115, no.3, pp.81-86, Nov [4] P. C. Ng, and S. C. Liew, Throughput analysis of IEEE multi-hop ad hoc networks, IEEE/ACM Trans. Networking, vol. 15, no. 2, pp , Apr. 27. [5] Y. D. Barowski, S. Biaz, and P. Agrawal, Towards the Performance Analysis of IEEE in Multi-hop Ad-Hoc Network, Proc. WCNC, New Orleans, USA, vol. 1, pp. 1-16, Mar. 25. [6] J. Shi, H. Sekiya, K. Sanada, N. Komuro, and S. Sakata, Delay Analysis for IEEE String Topology Multi-hop Networks, Proc. NCSP, Hawaii, USA, vol. 15, no. 2, pp , Mar [7] K. Sanada, J. Shi, N. Komuro, and H. Sekiya, End-to-end delay analysis for IEEE string-topology multi-hop networks, IEICE Trans. on Communications, vol. E98-B, no. 7, pp , July [8] A. Kumar, E. Altman, D. Miorandi, and M. Goyal,, New insights from a fixed point analysis of single cell IEEE Wireless LANs, IEEE/ACM Trans. Networking, vol. 15, no. 3, pp , Jun. 27. Collision probability (a) (b) (c).3 5 Network (d) 2 3 (a): (b): (c): (d): ( ) 79

6 Carrier sense airtime (a) 1 Network (b) (a) (b) (c) Collision probability.3 5 Network (d) 3 4 (a): (c): (b): (d): ( ) (c) 8

7 Collision probability Network (d) 4 3 (a): (c): (b): (d): ( ) Carrier sense airtime 1 Network (c) (a) Collision probability.3 5 Network (d) 5 4 (a): (c): (b): (d): ( ) (b) 81