Femto-Matching:Efficient Traffic Offloading in Heterogeneous Cellular Networks Wei Wang,Xiaobing Wu,Lei Xie and Sanglu Lu Nanjing University April 28,2015 日，+司1三13卡三分Q0 1/1
Femto-Matching: Efficient Traffic Offloading in Heterogeneous Cellular Networks Wei Wang , Xiaobing Wu, Lei Xie and Sanglu Lu Nanjing University April 28, 2015 1/1
Heterogeneous Cellular Networks ti femto-cell Micro-cell femto-cell femto-cell Marco-cell femto-cell Micro-cell femto-cell Cellular networks use multiple layers of basestations to im- prove spatial utility Small cells such as femtocell or WiFi APs help offloading the traffic form the macro-cell 2/1
Heterogeneous Cellular Networks Micro-cell femto-cell femto-cell femto-cell femto-cell Micro-cell femto-cell Marco-cell • Cellular networks use multiple layers of basestations to improve spatial utility • Small cells such as femtocell or WiFi APs help offloading the traffic form the macro-cell 2/1
User Association Problem 5m0849 WLAN Mobile devices can connect to dlink-nju Secured (WeS available) 0 multiple basestations Hiwif611 Open Basestations provide different Node2 Open service qualities OpenWrt_5.1 Coen Traditional approach SuperMan Secured (WPS available) 名 strongest signal wlantest lowest price Cpen (WPS available) highest transmission rate wlantest5G Open (WPS avarahle) Xiaomi_4CB9 Scan WLAN Direct 日+①4三1字卡2分QC 3/1
User Association Problem • Mobile devices can connect to multiple basestations • Basestations provide different service qualities • Traditional approach - strongest signal - lowest price - highest transmission rate 3/1
Problems for Existing Approaches Scenarios of suboptimal solutions 1M femto A ●For the user overly crowded basestations .For the carrier low utilization of femto-cells overload of marco-cells femto B 口，01三13卡至QC 4/1
Problems for Existing Approaches Scenarios of suboptimal solutions • For the user - overly crowded basestations • For the carrier - low utilization of femto-cells - overload of marco-cells femto A femto B 1M 1M 1M 1M 4 M 4/1
Problems for Existing Approaches Scenarios of suboptimal solutions 1.3M 1.3M femto A ●For the user -overly crowded basestations .For the carrier low utilization of femto-cells 2M overload of marco-cells femto B 日，+司1三13卡三分Q0 4/1
Problems for Existing Approaches Scenarios of suboptimal solutions • For the user - overly crowded basestations • For the carrier - low utilization of femto-cells - overload of marco-cells femto A femto B 1.3M 2M 1!"M 1.3M 2 M 4/1
Problems for Existing Approaches Associate to Cannot connect Scenarios of suboptimal solutions to BS A due to macro-cell resource constraints For the user 1M -overly crowded basestations 。For the carrier low utilization of femto-cells overload of marco-cells emto B 4/1
Problems for Existing Approaches Scenarios of suboptimal solutions • For the user - overly crowded basestations • For the carrier - low utilization of femto-cells - overload of marco-cells femto A femto B 1M 1.3 M 1M 1M 1.3 M Cannot connect to BS A due to resource constraints 1M Associate to macro-cell 1.3 M 4/1
Problems for Existing Approaches Scenarios of suboptimal solutions ●For the user 1M 1M -overly crowded basestations 。For the carrier -low utilization of femto-cells overload of marco-cells femto B 日，+司1三13卡三分Q0 4/1
Problems for Existing Approaches Scenarios of suboptimal solutions • For the user - overly crowded basestations • For the carrier - low utilization of femto-cells - overload of marco-cells femto A femto B 1M 1 M 1M 1M 1 M Cannot connect to BS A due to resource constraints 1M Associate to macro-cell 1M 1M 4/1
Randomly Deployed Network 70 60 50 40 30 20 10 VI 10 203040 50 60 meters An example for randomly deployed network 5/1
Randomly Deployed Network 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70 meters meters An example for randomly deployed network 5/1
Randomly Deployed Network 70 60 50 40 30 20 10 203040 40 60 70 meters “orphan nodes'"20%→5% 日+回1三1交非三勺QG 5/1
Randomly Deployed Network 0 10 20 30 40 40 60 70 0 10 20 30 40 50 60 70 meters meters “orphan nodes” 20% → 5% 5/1
Key Challenges Misaligned objectives for users and network operators Users want better throughput Operators want better resource utilization Both the femto-cells and the users are randomly distributed Require a global view to fully optimize the system Mobile devices move all the time One device usually only associates with one basestation 日14回”1三”11至分风C 6/1
Key Challenges • Misaligned objectives for users and network operators - Users want better throughput - Operators want better resource utilization • Both the femto-cells and the users are randomly distributed • Require a global view to fully optimize the system • Mobile devices move all the time • One device usually only associates with one basestation 6/1