Android LAN TCP Android. TCP A Proposal of TCP Control Method based on its Environment for Wireless Access of Android Terminals and Development of Communication Control Middleware KAORI MIKI, HIROMI HIRAI, SANEYASU YAMAGUCHI and MASATO OGUCHI In recent years, with the rapid growth of smart phone market, Android attracts attentions as software platform of embedded system. Previous mobile phones control network communication individually and independently. Some studies have been performed so far improve communication behavior in such a way. It becomes possible that a mobile terminal can exchange information among terminals and control in a cooperative way. Because recent phones, especially smart phones which is called high performance mobile phone, come to have better performance. In this paper, on the premise of such cooperation, we propose middleware which uses original method of communication that considers around condition and uses bandwidth effectively. 1. Android 1). 2) 3) LAN Ochanomizu University Kogakuin University Android 4) TCP 11) 176
2 TCP TCP 3 4 5 Android 2 TCP 6 TCP 7 8 ROM ROM Android 2. 2.1 LAN TCP Android Android TCP-CUBIC 5) TCP TCP-CUBIC TCP 6)7) Congestion Notification Loss Notification Linux 8) 1 1 Android Android Android TCP 2.2 TCP TCP TCP TCP TCP 2 TCP TCP TCP 177
TCP 10) TCP TCP 7 3. 3.1. Android HTC HT-03A ( A) Samsung Nexus S ( B) 2 TCP 3 TCP Android 1 TCP TCP TCP 4 6 3 TCP 4 5 6 4 TCP 1 Experimental Environment A Model number HT-03A Firmware version 2.1-update1 Baseband version 62.50S.20.17H_2.22.19.26I Kernel version 2.6.29-00481-ga8089eb-dirty Build number aosp_sapphire_us-eng 2.1-update1 ERE27 B Model number Nexus S Firmware version 2.3.4 Baseband version I9023XXKD1 Kernel version 2.6.35.7-kaori1198-ge382d80-dirty Build number GRJ22 OS Fedora release 10 (Cambridge) CPU Intel(R) Pentium(R) 4 CPU 3.00GHz Main Memory 1GB 1. iperf-2.0.4 12) Android. arm- 2008q3 13). 3 3 IEEE802.11g 2 Android 4 LAN. 5. 3.2 4 178
2 4. A 2009 B 2010 Android A B TCP 16ms A 10Mbps B 20Mbps A B 1:2 1:2 A 2 B 2 4 5 4 802.11g 54Mbps B 20Mbps 1:2 A 4. TCP 3.2 2 TCP RTT B A TCP TCP 0 default 20 original 70 1 default 20 original 70 2 default 20 original 70 4 default 20 original 70 8 default 20 original 70 16 default 20 original 100 32 default 30 original 100 64 default 55 original 100 128 default 55 original 100 256 default 100 original 100 TCP default OS TCP TCP original TCP 3.2 default original 2 B OS A TCP TCP 6 2. 5 2 A B 5 4 6 4 2 179
A TCP 2 A B TCP. A TCP TCP- CUBIC TCP B TCP. 5. 3 4 A 4 B TCP CA_STATE. 5.1 4 7 8 A B 4 8 B 4 Open 1 4 Disorder CWR Recovery Loss 9 A 4 CA_STATE 7 A 4 7 8 A B 5.2 4 CA_STATE 9 10 A B 4 CA_STATE CA_STATE TCP 0 10 B 4 CA_STATE 9 10 A B 180
A B B TCP 3 A A B TCP TCP 6. TCP A A B TCP. A TCP B 6.1 B A TCP B TCP 3.2 4 TCP B B TCP A TCP B B A B A TCP B TCP A TCP 3.2 3 6.2 TCP A B 3 B TCP RTT 3 TCP 2 B A TCP TCP 0 A TCP 30 default 70 1 A TCP 30 default 70 2 A TCP 35 default 70 4 A TCP 35 default 70 8 A TCP 35 default 70 16 A TCP 40 default 70 32 A TCP 50 default 70 64 A TCP 65 default 70 128 A TCP 80 default 70 256 A TCP 80 default 70 A 11 11 4 Android 3 11 B TCP A 4 OS A: B 1:2 3.5(Mbps):7(Mbps) TCP B A 7. 7.1 B A TCP OS TCP proc Android Dalvik VM 181
Android Android C bionic 14 12 2 12 0.5 UDP A A B TCP TCP 13 B A 50 B 3 TCP 3 TCP 13 7.2 Android TCP A B RTT=8ms 14 1 A 50 10 3 Android 30 3 Android 50 A 1 10 1 TCP TCP 2 TCP 3 3 TCP TCP 7.3 TCP 1 2 15 16 4 Android (s) 15 16 A B 1 2 B A B A B TCP A 182
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