PRODUCT REVIEW ICOM IC-7600 HF and - Two-Way Radios - 2-Way Radios
Two-way IC
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Transcript of Two-way IC
![Page 1: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/1.jpg)
Two-way Interference Channels
TexPoint fonts used in EMF.
ITA 2012
Feb. 7
Changho Suh
MIT
Joint work with David Tse & I-Hsiang Wang
![Page 2: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/2.jpg)
Two-way Communication
Network
![Page 3: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/3.jpg)
Two-way Communication
Network
Forward
Backward
![Page 4: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/4.jpg)
Two-way Communication
Network
Communication links are two-way
![Page 5: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/5.jpg)
Two-way Communication
Network
The two-way nature allows interaction
Communication links are two-way
![Page 6: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/6.jpg)
Two-way Communication
Network
Does interaction provide a gain in capacity?
The two-way nature allows interaction
Communication links are two-way
![Page 7: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/7.jpg)
Interaction
Network
![Page 8: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/8.jpg)
Interaction
Network
Prerequisite: Understanding the role of feedback
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Interaction
Network
Prerequisite: Understanding the role of feedback
enabled through Feedback
![Page 10: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/10.jpg)
Interaction
Network
Prerequisite: Understanding the role of feedback
enabled through Feedback
Does feedback provide a gain in capacity?
![Page 11: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/11.jpg)
Feedback
Point-to-point
![Page 12: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/12.jpg)
Feedback
Point-to-point
Shannon 56
![Page 13: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/13.jpg)
Feedback
Point-to-point
Feedback cannot increase capacity Shannon 56
![Page 14: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/14.jpg)
Feedback
Point-to-point
Feedback cannot increase capacity Shannon 56
Perfect & cost-free
![Page 15: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/15.jpg)
Feedback
Multiple access
![Page 16: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/16.jpg)
Feedback
Multiple access
Feedback can increase capacity for MACs
(Gaarder-Wolf 75, Cover-Leung 81)
![Page 17: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/17.jpg)
Feedback
Multiple access
Feedback can increase capacity for MACs
(Gaarder-Wolf 75, Cover-Leung 81)
However, gain for AWGN is bounded (Ozarow 84)
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Feedback under Interference
![Page 19: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/19.jpg)
Feedback under Interference
Feedback can provide unbounded gain
(Kramer ‘02, Suh-Tse ‘09)
![Page 20: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/20.jpg)
Feedback under Interference
Perfect & cost-free
Feedback can provide unbounded gain
(Kramer ‘02, Suh-Tse ‘09)
![Page 21: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/21.jpg)
Feedback under Interference
Perfect & cost-free
Feedback can provide unbounded gain
(Kramer ‘02, Suh-Tse ‘09)
What if we count feedback cost?
![Page 22: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/22.jpg)
Net Feedback Gain?
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Net Feedback Gain?
Bit Pipe
Vahid-Suh-Avestimehr 11:
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Net Feedback Gain?
Bit Pipe
One bit of feedback provides one bit of a capacity increase
Vahid-Suh-Avestimehr 11:
![Page 25: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/25.jpg)
Net Feedback Gain?
Bit Pipe
One bit of feedback provides one bit of a capacity increase
Vahid-Suh-Avestimehr 11:
No net feedback gain
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Two-way IC: Feedback Over-the-IC
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Two-way IC: Feedback Over-the-IC
![Page 28: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/28.jpg)
Two-way IC: Feedback Over-the-IC
Not necessarily same
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Two-way IC: Feedback Over-the-IC
![Page 30: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/30.jpg)
Two-way IC: Feedback Over-the-IC
![Page 31: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/31.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
Feedback
Different symbol rates
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Two-way IC: Feedback Over-the-IC
Forward
time
time
Feedback
![Page 33: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/33.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
Feedback
![Page 34: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/34.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
(Avestimehr-Diggavi-Tse model ’07)
Feedback
![Page 35: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/35.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
(Avestimehr-Diggavi-Tse model ’07)
Feedback
![Page 36: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/36.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
(Avestimehr-Diggavi-Tse model ’07)
Feedback
![Page 37: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/37.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
(Avestimehr-Diggavi-Tse model ’07)
Feedback
![Page 38: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/38.jpg)
Two-way IC: Feedback Over-the-IC
Forward
time
time
(Avestimehr-Diggavi-Tse model ’07)
Feedback
![Page 39: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/39.jpg)
Sum Capacity
Theorem:
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Sum Capacity
Theorem:
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Sum Capacity
Theorem:
![Page 42: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/42.jpg)
Sum Capacity
Theorem:
![Page 43: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/43.jpg)
Net Feedback Gain
![Page 44: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/44.jpg)
Net Feedback Gain
Two ways of using backward IC
![Page 45: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/45.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages (1)
![Page 46: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/46.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
(1)
![Page 47: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/47.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
(1)
![Page 48: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/48.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
capacity gain
(1)
![Page 49: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/49.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
capacity gain
(1)
![Page 50: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/50.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
capacity gain
(1)
![Page 51: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/51.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
capacity gain
(1)
![Page 52: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/52.jpg)
Net Feedback Gain
Two ways of using backward IC
Send independent backward messages
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
capacity gain
(1)
![Page 53: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/53.jpg)
Net Feedback Gain
Two ways of using backward IC
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
(2) Feedback purpose
capacity gain
Send independent backward messages (1)
![Page 54: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/54.jpg)
Net Feedback Gain
Two ways of using backward IC
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
(2) Feedback purpose
$
capacity gain
(cost)
Send independent backward messages (1)
![Page 55: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/55.jpg)
Net Feedback Gain
Two ways of using backward IC
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
(2) Feedback purpose
$
0.5 bits
capacity gain
(cost)
Send independent backward messages (1)
![Page 56: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/56.jpg)
Net Feedback Gain
Two ways of using backward IC
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
(2) Feedback purpose
$
0.5 bits
1 bit
capacity gain
(cost)
Send independent backward messages (1)
![Page 57: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/57.jpg)
Net Feedback Gain
Two ways of using backward IC
(2) Send feedback signals for aiding forward-
message tx
Capacity
Gain
(1) First purpose
(2) Feedback purpose
$
0.5 bits
1 bit
Net Gain: 0.5 bits
capacity gain
(cost)
Send independent backward messages (1)
![Page 58: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/58.jpg)
Achievable Scheme
![Page 59: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/59.jpg)
Achievable Scheme
No feedback
![Page 60: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/60.jpg)
Achievable Scheme
No feedback
![Page 61: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/61.jpg)
Achievable Scheme
No feedback
![Page 62: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/62.jpg)
Achievable Scheme
No feedback
![Page 63: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/63.jpg)
Achievable Scheme
Perfect feedback
![Page 64: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/64.jpg)
Achievable Scheme
Time 1
Perfect feedback
![Page 65: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/65.jpg)
Achievable Scheme
Time 1 Time 1
Perfect feedback
![Page 66: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/66.jpg)
Achievable Scheme
decode
Time 1 Time 1
Perfect feedback
![Page 67: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/67.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1
Perfect feedback
![Page 68: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/68.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2
Perfect feedback
![Page 69: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/69.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2
Perfect feedback
![Page 70: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/70.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2 Time 2
Perfect feedback
![Page 71: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/71.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2 Time 2
Perfect feedback
![Page 72: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/72.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2 Time 2
Perfect feedback
![Page 73: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/73.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2 Time 2
Perfect feedback
![Page 74: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/74.jpg)
Achievable Scheme
decode
decode
Time 1 Time 1 Time 2 Time 2
![Page 75: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/75.jpg)
Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
![Page 76: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/76.jpg)
Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
![Page 77: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/77.jpg)
Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
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Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
![Page 79: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/79.jpg)
Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
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Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
![Page 81: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/81.jpg)
Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
![Page 82: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/82.jpg)
Achievable Scheme
Time 1 Time 1 Time 2 Time 2
want
want
![Page 83: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/83.jpg)
Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
want
want
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Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
want
want
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Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Side info
want
want
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Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Side info
want
want
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Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Side info
want
want
![Page 88: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/88.jpg)
Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Side info
want
want
![Page 89: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/89.jpg)
Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Optimal!
Side info
want
want
![Page 90: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/90.jpg)
Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Optimal!
Side info
want
want
Can feed back 2 bits through 1-bit-capacity backward IC!
![Page 91: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/91.jpg)
Achievable Scheme
Side info
Time 1 Time 1 Time 2 Time 2
Optimal!
Side info
want
want
Can feed back 2 bits through 1-bit-capacity backward IC!
Net feedback gain
![Page 92: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/92.jpg)
Extension: Four-Message Two-way IC
![Page 93: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/93.jpg)
Extension: Four-Message Two-way IC
Interaction provides a significant capacity
increase
![Page 94: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/94.jpg)
Extension: Four-Message Two-way IC
Interaction provides a significant capacity
increase
Mixing forward-&-backward messages
can provide a larger gain
![Page 95: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/95.jpg)
Related Work
Sahai-Aggarwal-Yuksel-Sabharwal `09
Two-way IC with two forward messages
![Page 96: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/96.jpg)
Related Work
Sahai-Aggarwal-Yuksel-Sabharwal `09
No net feedback gain
Two-way IC with two forward messages
![Page 97: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/97.jpg)
Related Work
Sahai-Aggarwal-Yuksel-Sabharwal `09
No net feedback gain
Two-way IC with two forward messages
We consider arbitrary forward-backward ICs
![Page 98: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/98.jpg)
Related Work
No
Gain
?
Net
Gain
Net
Gain
Sahai-Aggarwal-Yuksel-Sabharwal `09
No net feedback gain
Two-way IC with two forward messages
We consider arbitrary forward-backward ICs
![Page 99: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/99.jpg)
Related Work
No
Gain
?
Net
Gain
Net
Gain
Sahai-Aggarwal-Yuksel-Sabharwal `09
No net feedback gain
Two-way IC with two forward messages
Open
We consider arbitrary forward-backward ICs
![Page 100: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/100.jpg)
Conclusion
1
2
3
![Page 101: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/101.jpg)
Conclusion
Sum capacity of two-way IC (except for some channel regimes)
1
2
3
![Page 102: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/102.jpg)
Conclusion
Sum capacity of two-way IC (except for some channel regimes)
A new viewpoint on the use of backward IC
1
2
3
![Page 103: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/103.jpg)
Conclusion
Sum capacity of two-way IC (except for some channel regimes)
A new viewpoint on the use of backward IC
1
2
3
Feedback purpose
Original purpose
(send ind. backward mgs)
>
![Page 104: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/104.jpg)
Conclusion
Sum capacity of two-way IC (except for some channel regimes)
A new viewpoint on the use of backward IC
1
2
3
Feedback purpose
Original purpose
(send ind. backward mgs)
>
side info
no side info
![Page 105: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/105.jpg)
Conclusion
Sum capacity of two-way IC (except for some channel regimes)
A new viewpoint on the use of backward IC
Feedback can provide a net increase in capacity
1
2
3
Feedback purpose
Original purpose
(send ind. backward mgs)
>
side info
no side info
![Page 106: Two-way IC](https://reader034.fdocuments.us/reader034/viewer/2022051521/5861bc621a28ab0e308c2d5f/html5/thumbnails/106.jpg)
Conclusion
Sum capacity of two-way IC (except for some channel regimes)
A new viewpoint on the use of backward IC
Feedback can provide a net increase in capacity
1
2
3
Feedback purpose
Original purpose
(send ind. backward mgs)
>
side info
no side info
Reference: http://arxiv.org/abs/1202.5014