truthful and non-monetary mechanism for direct data exchange
DESCRIPTION
Truthful and Non-Monetary Mechanism for Direct Data Exchange. I-Hong Hou, Yu-Pin Hsu, and Alex Sprintson. Direct Data Exchange in Wireless D 2D Communications. Exchange data locally instead of getting all packets from the base station. A,B. A. B. A,B. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/1.jpg)
Truthful and Non-Monetary Mechanism for Direct Data Exchange
I-Hong Hou, Yu-Pin Hsu, and Alex Sprintson
![Page 2: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/2.jpg)
Direct Data Exchange in Wireless D2D Communications
• Exchange data locally instead of getting all packets from the base station
A BA,B
A,B
![Page 3: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/3.jpg)
Direct Data Exchange in Wireless D2D Communications
• Exchange data locally instead of getting all packets from the base station
A BA,B
A,BA B
![Page 4: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/4.jpg)
Direct Data Exchange in Wireless D2D Communications
• Exchange data locally instead of getting all packets from the base station
A BA,B
A,BA B
A B
![Page 5: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/5.jpg)
Direct Data Exchange in Wireless D2D Communications
• Exchange data locally instead of getting all packets from the base station
A BA
B
A B
![Page 6: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/6.jpg)
Direct Data Exchange in Wireless D2D Communications
• Exchange data locally instead of getting all packets from the base station
A BA
B
A
B
![Page 7: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/7.jpg)
Benefits of Wireless P2P
• Exchange data locally requires less power• Reduce power consumption• Reduce interference• Increase spatial reuse and hence total
system capacity
• Challenge: How to provide incentives for clients to cooperate?
![Page 8: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/8.jpg)
Network Model
• Each client has all but one unique file, which it needs
• The size of a file = Z bits• All clients can communicate with each other
A B
Need: D
C A B
Need: C
D A D
Need: B
C D B
Need: A
C
![Page 9: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/9.jpg)
Incentive Model
• Each client has a secret valuation vi ≤1 for its needed file
• Each client pays some transmission cost for the amount of upload data
A B
v1 = 0.7
C A B
v2 = 0.6
D A D
v3 = 0.5
C D B
v4 = 0.1
C
![Page 10: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/10.jpg)
Incentive Model
• The goal of a client: Maximize net utility vi1(receive file) - (amount of upload)/Z
A B
v1 = 0.7
C A B
v2 = 0.6
D A D
v3 = 0.5
C D B
v4 = 0.1
C
![Page 11: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/11.jpg)
Bidding Model
• Each client submits a bid bi to a broker• The broker determines how much data a client
uploads, and what packets it should uploads
A B
v1 = 0.7
C A B
v2 = 0.6
D A D
v3 = 0.5
C D B
v4 = 0.1
C
![Page 12: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/12.jpg)
An Example
A B
b1 = 0.8
C A B
b2 = 0.2
D A D
b3 = 0.9
C D B
b4 = 0.4
C
![Page 13: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/13.jpg)
An Example
A B
b1 = 0.8
C A B
b2 = 0.2
D A D
b3 = 0.9
C D B
b4 = 0.4
C
Upload 0.6Z (A+B)
Upload nothing
Upload 0.6Z (A+D)
Upload 0.4Z (B+D)
![Page 14: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/14.jpg)
An Example
A B
b1 = 0.8
C
Upload 0.6Z (A+B)
Upload nothing
Upload 0.6Z (A+D)
Upload 0.4Z (B+D)
• D = (A+D)-A = (B+D)-B• Can obtain all bits of D
![Page 15: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/15.jpg)
An Example
A B
b1 = 0.8
C A B
b2 = 0.2
D A D
b3 = 0.9
C D B
b4 = 0.4
C
Upload 0.6Z (A+B)
Upload nothing
Upload 0.6Z (A+D)
Upload 0.4Z (B+D)
D B A
![Page 16: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/16.jpg)
An Example
Net utility 0.7-0.6=0.1
0 0.5-0.6= -0.1
0.1-0.4= -0.3
v1 = 0.7 v2 = 0.6 v3 = 0.5 v4 = 0.1
Upload 0.6Z
Upload nothing
Upload 0.6Z
Upload 0.4Z
D B A
![Page 17: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/17.jpg)
Goal of this Work
• Design a “truthful” broker policy• Truthful: Every client maximizes its utility by
choosing bi = vi
• The policy should also achieve high total net utility
Why not simply apply VCG auction?
![Page 18: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/18.jpg)
Auction Wireless P2PEach client submits a bid
Each client submits a bid
![Page 19: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/19.jpg)
Auction Wireless P2PEach client submits a bid
Each client submits a bid
Auctioneer determines who wins the auction, and how much each winner pays
Broker determines how much a client uploads, and who can download its file
Comparable by treating uploads as payments, clients that download files as winners
![Page 20: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/20.jpg)
Auction Wireless P2PEach client submits a bid
Each client submits a bid
Auctioneer determines who wins the auction, and how much each winner pays
Broker determines how much a client uploads, and hence who can download its file
Decisions on selecting winners and payments are independent
Decision on upload rates limits who can download its file
![Page 21: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/21.jpg)
Proposed Protocol
• Every client submits a bid bi
• Find the largest set S such that, for all i in S, bi≥ 1/(|S|-1)
• S = {1,2,3}, b1, b2, b3≥ 1/2• S = {1,2,3,4}, b4< 1/3• Largest set is {1,2,3}
b1=0.7 b2=0.6 b3=0.6 b4=0.2
![Page 22: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/22.jpg)
Proposed Protocol
• Every client submits a bid bi
• Find the largest set S such that, for all i in S, bi≥ 1/(|S|-1)
• Every client in S uploads Z/(|S|-1) bits containing a linear combination of all files that other clients in S needs
• Each client in S receive Z bits, and hence can obtain the file it needs
• Clients not in S do not obtain needed files
![Page 23: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/23.jpg)
Theorem:This protocol is truthful
Note: The broker is only conceptual. The policy can be implemented in a distributed fashion by letting each client run the broker policy.
![Page 24: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/24.jpg)
Performance Analysis
• Sort clients such that b1≥b2≥b3≥…• The set S must be the form of {1,2,…,n}• Client i does not obtain its file only if bi<1/(i-1)Theorem:In terms of total net utility, the difference between this protocol and one maximizing total net utility is at most 1+1+1/2+1/3+…+1/(N-1), where N is the number of clients
![Page 25: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/25.jpg)
Numerical Results
• Assign vi to each client uniformly at random from [0,1]
• Compare the difference in total net utility between our proposed protocol and a protocol that maximizes total net utility
![Page 26: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/26.jpg)
![Page 27: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/27.jpg)
Extension: Dependency Graph
• Some clients may not be able to exchange file– A client may miss some files that it does not need– Some clients may be too far away to communicate
• Define a “dependency graph”• Each client is a node in the graph• Two nodes have an edge between them if the
two clients can exchange needed files
![Page 28: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/28.jpg)
Solutions for Dependency Graph
1. Find the largest clique such that every node in the clique has bi≥ 1/(size of clique-1)
2. Each node in the clique uploads Z/(size of clique-1) bits
3. Repeat Step 1
Theorem:This protocol is truthful
![Page 29: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/29.jpg)
Extension: Some Clients Need the Same File
Need: Abi =0.5
Need: Abi =0.3
Need: Abi =0.2
• Some clients need the same file• Each client has all but one files• Merge them into one, whose bid is (number of
merged clients)x(minimum bid)• If they are selected in S, they divide the
amount of upload evenly
![Page 30: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/30.jpg)
Extension: Some Clients Need the Same File
Need: Abi =0.5
Need: Abi =0.3
Need: Abi =0.2
• Some clients need the same file• Each client has all but one files• Merge them into one, whose bid is (number of
merged clients)x(minimum bid)• If they are selected in S, they divide the
amount of upload evenly
![Page 31: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/31.jpg)
Extension: Some Clients Need the Same File
• Some clients need the same file• Each client has all but one files• Merge them into one, whose bid is (number of
merged clients)x(minimum bid)• If they are selected in S, they divide the
amount of upload evenly
Need: Abi =0.6
![Page 32: Truthful and Non-Monetary Mechanism for Direct Data Exchange](https://reader035.vdocuments.us/reader035/viewer/2022062315/56816295550346895dd30bd4/html5/thumbnails/32.jpg)
Summary
• Study the problem of direct data exchange from the perspective of game theory
• While the game looks like an auction, results of auction theory do not apply
• Propose a non-monetary protocol that is truthful
• The protocol can be extended to various scenarios