List of unsolved problems in information theory

This article lists some unsolved problems in information theory which are separated into source coding and channel coding. There are also related unsolved problems^[1] in philosophy.

Channel coding

• Capacity of a network:^[2] The capacity of a general wireless network is not known. There are some specific cases for which the capacity is known, such as the AWGN channel and fading channel.
• Capacity of the broadcast channel:^[3][4] The capacity of the broadcast channel, or the case in which a single transmitter is sending information to many receivers is unknown in general, though it is known for several specific cases.
• Capacity of the interference channel (Two User): The capacity of the interference channel, in the case where there are two transmitter and receiver pairs that interfere among each other, is unknown in general. Capacity is known in special cases: strong interference regime, injective-deterministic. Capacity is known in approximate sense or with in a gap for: injective-semi-deterministic, additive white Gaussian noise with per block power constraint.
• Capacity of the two-way channel.^[5][6] The capacity of the two-way channel (a channel in which information is sent in both directions simultaneously) is unknown.
• The capacity of Aloha:^[7] The ALOHAnet used a very simple access scheme for which the capacity is still unknown, though it is known in a few special cases.
• Quantum capacity: The capacity of a quantum channel is in general not known.^[8]

There are many unsolved problems in coding theory:^[9] and in related areas.^[10][11]

Source coding

Distributed source coding: The best way to compress multiple correlated information sources that do not communicate with each other is not known.

References

1. Adriaans, Pieter. "Open Problems in the Study of Information and Computation". Retrieved 21 June 2013.
2. Cover, Thomas. Elements of Information Theory. Wiley-Interscience. ISBN 978-0471062592.
3. Cover, Thomas (Oct 1998). "Comments on Broadcast Channels". IEEE Trans Inf Theory. 44 (6): 2524.
4. Sridharan, Arvind. "Broadcast Channels" (PDF). Notre Dame. Retrieved 6 July 2014.
5. Shannon, Claude (1961). "Two-way communication channels". Proc Fourth Berkeley sump on Mathematical Statistics and Probability. 1: 611.
6. meeuwissen, Erik (16 Aug 1998). "The Origin of Two-Way Channels". Proc ISIT. I: 185.
7. Medard, Muriel (March 2004). "Capacity of Time-Slotted ALOHA Packetized Multiple-Access Systems Over the AWGN Channel" (PDF). EEE Transactions on Wireless COMMUNICATIONS. 3 (2). Retrieved 11 July 2014.
8. Shor, Peter (2000). "Quantum Information Theory: Results and Open Problems" (PDF). Geom. Funct. Anal.: 816–838.
9. David Joyner; Jon-Lark Kim (2010). Selected Unsolved Problems in Coding Theory. New York: Springer.
10. Longo, Giuseppe (1975). Information theory: new trends and open problems.
11. Tse, David (1996). "It's Easier to Approximate" (PDF). Information Theory Society Newsletter. Retrieved 26 June 2013.