Two Systems to Restructure Mobile Wireless Services

Size: px

Start display at page:

Download "Two Systems to Restructure Mobile Wireless Services"

Sophia Rogers
6 years ago
Views:

1 Two Systems to Restructure Mobile Wireless Services Rajiv Chakravorty Cambridge University

2 Mobiles vs PCs as Primary Digital Device 4B Mobile Penetration 3B 2B PC Penetration 1B Paradigm Paradigm shift shift with with Mobile Mobile Computing Computing

3 India/China Calling Where do you think 4+ Billion mobile users would be?

4 Two new directions How to enable an open mobile ecosystem? MoB System Architecture User reputation and financial incentive mgmt. Application evaluation How to restructure voice-centric mobile networks to support Video? MobiStream System Virtual Channels Perceptual Slice-structured Video

5 BUY-1-GET-1-FREE Mobile Operators.. s e s c i e v c i e v d e d d e d k e c. k o s c. L u o s ) o L u t i M ) o I uuit M S q I ( i S. q b ( i s u tts. b t c u o a t c r n t o a r n e n t o g n e c a o g r ee c a e l r v b e l i o v x b i C Co IInnfflleex

Sprint google No No (fine-grained) (fine-grained) Competition.

6 Today s (Closed) Mobile Architecture Applications and mobile devices aggressively controlled by cellular operators Verizon AT&T VZW Yahoo Sprint google No No (fine-grained) (fine-grained) Competition. Competition. No No Choice. Choice. Lack Lack of of Innovation. Innovation.

7 Why Open Closed Networks? Foster Foster Innovation. Innovation. Respect Respect Users Users Choice. Choice. Enable Enable (fine-grained) (fine-grained) Competition. Competition.

8 Fundamental Design Principles

9 ACT 1996 Restructured US telecom Recall Recall that that restructuring restructuring enabled enabled fine-grained fine-grained competition competition for for telecom telecom products products && services services

10 Today s (Closed) Architecture VZW Verizon AT&T Yahoo Sprint ebay No No User User Choice. Choice. Lack Lack of of Innovation. Innovation. No No (fine-grained) (fine-grained) Competition. Competition.

11 Tomorrow's Open Mobile Architecture Mobile Bazaar (MoB) Loc Ba nd w on ati idth Bandw Sh are dw eb C ac he P 2 P idt h AT&T le Fi Verizon Mobile Mobile devices devices can can independently independently create create and and sell sell services services (aka (aka 'open' 'open' market market model) model)

12 Scenario #1: Bandwidth Aggregation Mobile Bazaar (MoB) Band widt h AT&T h idt dw Ban Verizon Enables Enables distributed distributed wireless wireless diversity diversity decisions decisions with with mobile mobile users/devices users/devices

13 Scenario #2: P2P file transfer service Mobile Bazaar (MoB) p2p fil file p 2 p t e tr ansf er sf ran er Enables Enables flexible flexible customization customization of of services services based based on on user user or or app app needs needs (disconnected (disconnected mode) mode)

14 Scenario #3: Opportunistic Services Mobile Bazaar (MoB) Location information Enables Enables opportunistic opportunistic time-scale time-scale service service interactions interactions (disconnected (disconnected mode) mode)

15 The MoB Advantage Better Performance thru Wireless Diversity Financial incentive for Collaborations Flexible customization of services Network Diversity Channel Diversity Technology Diversity Enables flexible, application-level service trades Users choose services based on price, signal, location, etc.

16 What are MoB environments? Metros Conferences Shops/Malls Buses/Trains

MoB Contact time is Variable 80 70 % of Users

Observer-based Opportunistic Contacts 30 20

17 MoB Contact time is Variable % of Users 60 ~40% stay more than 20 min Observer-based Opportunistic Contacts Signup-based Duration (in minutes)

18 Application-layer Services in MoB Hop-by-hop pair-wise service interactions Location A Ba n dw idt h B ed r a he h S ac C C How How can can A A be be made made to to trust trust B, B, or or trust trust C? C?

19 Vito Building trust thru Reputation Vito modeled on ebay 3rd Party Internet service 4 million transactions/day Misuse rate very low

20 Step 1 Devices register using key-pairs Vito Servers (Online Reputation System) Customer (A) e st i g Re Ra,t e rr es u q t Re g is t er Re q ue st Trader (B) Rb,t Devices Devices receive receive signed signed time-stamp time-stamp reputation reputation cert. cert. (online (online registration registration with with public public key) key)

21 Step 2 Service Interaction and Payment Customer (A) Trader (B) SLP Request (Rep. Cert.-A) SLP Response (Price, Rep. Cert.-B) Token (A, B, Price, t) Service Interactions Customer Customer makes makes payment payment first first to to receive receive service service (Disconnected (Disconnected No No Vito Vito during during interaction) interaction)

22 Step 3 Token Encash and Feedback Vito Servers (Online Reputation System) Customer (A) e Fe ck a db r fo B To ke n To En ke ca Trader ne sh Fe nc ed as ba he ck d fo ra (B) Token Customer encash provides is feedback positive only ifif dissatisfied of Token Customer encash provides is implicit implicit feedback positive onlyfeedback feedback dissatisfied of B. B.

23 Step 4 Reputation Updates at Night Vito Servers (Online Reputation System) Trader (B) Customer (A) Ra,t Rb,t A A small small transaction transaction fee fee is is the the incentive incentive for for Vito Vito

24 Remote file download example Microsoft Web Server MoB middleware installed in mobile devices Per-connection striping 3G -1 x DO v -E G 3 RT T C-2 C-1 MoB Middleware Media Streaming FTP WWW Objective: Download Microsoft Vista Logo Image Bluetooth/ WLAN.. Connection Mgr SLP Rep Mgr. Stripe Mgr Cache Mgr Discovery Layer

(5MB File) 600 500 High Churn 400 Medium Churn

25 P2P file transfer (testbed) 900 Download time (seconds) Bluetooth Traders w/churn (5MB File) High Churn 400 Medium Churn 300 Low Churn Block size (KB)

(cache not shared) MoB (w/ churn + shared cache) 60 MoB (w/o churn +

26 Collaborative Web Browsing (testbed) 90 3G-1xRTT (cache not shared) 3G-EvDO (cache not shared) Download Time (sec) 75 EvDO + 1xRTT (cache not shared) MoB (w/ churn + shared cache) 60 MoB (w/o churn + shared cache) 45% 45 38% 40% 41% 30 29% 15 0 w post s forge wisc s dot ebay

Opportunistic location (simulation) 550 500 Location Error (m) 450 400 350 12.

Automobiles 300 Density of automobiles (1000, 2000, 5000) 250 Manhattan random

27 Opportunistic location (simulation) Location Error (m) sq. km of 1000 Automobiles 2000 Automobiles mid-town Manhattan 5000 Automobiles 300 Density of automobiles (1000, 2000, 5000) 250 Manhattan random waypoint mobility model 200 Constant Speed, but randomly picked [Min, Max] 150 Adhoc b radios (80 m range, omni antenna) %-tage of GPS-enabled Vehicles 5% 5%GPS GPSnodes nodes~~72 72mmlocation locationaccuracy accuracy 18 20

28 Fundamental Contributions of MoB (ACM Mobicom 05)

29 Is Mobile Video ready for prime-time? There There are are challenges challenges

30 What is the fundamental issue with 2.5G + 3G Mobile Networks? (Source) Voice (AMR) (Channel) Link + PHY Source-channel optimized (Source) Video (H.263/4) (Channel) Link + PHY Source-channel Not Optimized Today's Today's Mobile Mobile Networks Networks engineered engineered for for Voice Voice

31 RLP f/r-dtch f/r-dtch BSC DATA (L2) Mobile Channels are Voice Optimized (e.g., CDMA1xRTT) MUX and QoS Sublayer PHY BTS F-PCDH Control Function Static. Static. Inflexible. Inflexible. No No Application Application Control. Control.

32 Mobile channels prone to bursty losses RLP = Enabled (stationary) RLP = Disabled (stationary) RLP = Enabled (Mobile)

33 Streaming Video over Voice Channels Voice s s ' s s k ' y k r aay oor d TToodNeettww N c i c t i t a SSttaVoice Channels Voice/Video/Data n n o i o s t i s t k a k r a r r r o e o e n w n t w e t e e gg NNe t t ee x x e NNe pttiivv aapadaptive d AAd Channels How How to to design design adaptive adaptive mobile mobile networks networks & & apps? apps?

of Retransmissions ViC1 ViC2 ViCn EC = Error Correction ViCs Abstraction Application-control

34 Our Solution: The Virtual Channels Concept Video Streaming (H.264) Applications Partitioned Video Content Rtx = No. of Retransmissions ViC1 ViC2 ViCn EC = Error Correction ViCs Abstraction Application-control for ViCs Link Layer RLP2 RLP1 RLPn MAC Dedicated Shared MAP: PHY Channels App-controlled App-controlled Channels. Channels. Dynamic. Dynamic. Flexible. Flexible.

35 Dynamic Channel Control How? Voice Apps TCP Video Who takes control? Think of a Slider. Dyn ami c Co ntr ol Link+Phy When the slider moves up or down, control of channel shifts between App & Network.

36 MobiStream The BIG Picture Video client Video Proxy Server Video streams Push Streaming App Layer Virtual Channels Virtual Channels Link Layer Link-Layer BTS Servers BSC/NodeB Internet How How to to intelligently intelligently stream stream video video over over ViCs? ViCs?

37 How to design intelligent video apps? No loss, 44.6 db 20% loss, 23.7dB 5% loss, 34.6 db 20% loss, 24.1 db Exploit Exploit perceptual perceptual value value in in Video Video Content Content

38 Perceptual Slice-structured Video Allzero Interleave ROI Checkboard (slice grp-1) slice grp-2 Percept-SS Specify Specify Region-of-Interest Region-of-Interest as as hints hints in in slices slices

39 Perceptual Slicing over ViCs Perceptual Video Codec (ROI segmented frame) Slice-1 over ViC-1 ViC-1 (RLP-E) ViC-2 (RLP-D) ViCs Abstraction Cellular Link + PHY Subsystem Slice-2 over ViC-2

40 Example Frame Partitioning using Motion Vectors Perceptual Perceptual codecs codecs may may segment segment frames frames with with MVs MVs

41 Experimental results for foreman QCIF video seq. (300 frames) Lossy channel Distribution A.FEC + ViCs (uncorrelated channels) A.FEC + MDC + ViCs (uncorrelated channels) raw decode (no loss) 50% > 1.0 db 30% > 2.5 db 10% ~ 4-7 db PSNR

42 Relative PSNR (db) Sliced Video benefit using ViCs Frame No. (GoP Sequence) Up Up to to 44 db db benefit benefit using using ViCs ViCs (Foreman) (Foreman)

43 Perceptual-SS Improves Subjective Picture Quality Checkboard Perceptual-SS

44 Fundamental Contributions of MobiStream (IEEE Infocom 06) Virtual Channels Perceptual Slice-structured Video Fine-grained error resilience Applications-defined link layer behaviour Gives partial control to applications Improves subjective video quality Gracefully overcomes bursty losses using slices Low-overhead Dynamic Channel Management

45 Other Contributions Flow Aggregation (IEEE Infocom 03) GPRSWeb (ACM Mobisys 03, 20K+ lines of code) Optimizing Wireless Services (ACM Mobicom 04) Mobile Access Router (ACM Mobisys 04) Exploiting diversity for Audio (IEEE Infocom 05) Wireless Integration and handovers (Percom 04)

46 Future Wireless Network services Innovative Wireless System Architectures, Applications and Services Spectrum-agile Mobile Radio Networks Mobile Multimedia Communication System Design

47 Next Generation Wireless Networks Innovative Wireless System Architectures, Applications and Services Spectrum-agile Mobile Networks Mobile Multimedia Communication System Design

48 Reputation system Vito Evaluation 500 users (fraction of them malicious) Services priced randomly (1 5 units ) Price increment/reduction factor (0.01) End-of-day model (the model) Up to 50 services/day (max. 1000)

49 Impact of User Selection Policy Services Left after 20 days Selection Policy Reputation Price Reputation/Price Good Users Malicious Users Virtual Currency left after 20 days Selection Policy Good Users Reputation Price Reputation/Price Malicious Users ~

50 Impact of Malicious Users Malicious %tage Services Left (20 days) Good Users Malicious 1% % % % % Reputation-driven Reputation-driven policies policies insensitive insensitive to to the the fraction fraction of of malicious malicious users users

51 Infrastructure and Testbed

52 Enterprise (Smart) Phones Entertainment Phones (Add. Video) Expression Phones (Voice+SMS) The World of Mobile Phones

MoB: A Mobile Bazaar for Wide Area Wireless Services. R.Chakravorty, S.Agarwal, S.Banerjee and I.Pratt mobicom 2005

MoB: A Mobile Bazaar for Wide Area Wireless Services R.Chakravorty, S.Agarwal, S.Banerjee and I.Pratt mobicom 2005 What is MoB? It is an infrastructure for collaborative wide-area wireless data services.