Multiple-access capacity as a rate region
Research context
postgraduate concept · established · As of 2026-10-10
For a two-sender discrete memoryless MAC with independent messages, the capacity region is the closure of rates bounded by I(X1;Y|X2,Q), I(X2;Y|X1,Q) and I(X1,X2;Y|Q), over laws p(q)p(x1|q)p(x2|q)p(y|x1,x2).
Key knowledge
For a two-sender discrete memoryless MAC with independent messages, the capacity region is the closure of rates bounded by I(X1;Y|X2,Q), I(X2;Y|X1,Q) and I(X1,X2;Y|Q), over laws p(q)p(x1|q)p(x2|q)p(y|x1,x2). Time-sharing Q convexifies the region. Independent conditional inputs are a hypothesis; feedback, cooperating encoders or input cost constraints change the region.
Values and equations
R1≤I(X1;Y|X2,Q); R2≤I(X2;Y|X1,Q); R1+R2≤I(X1,X2;Y|Q)
- R1,R2
- Independent sender rates, bits per channel use
- Q
- Time-sharing variable
- Y
- Common receiver output
Conditions and scope
- Independent messages, memoryless channel, asymptotic vanishing average error and permitted alphabets/costs are fixed.
- Rates are bits per channel use, and the closure includes boundary rates through limits.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Author checked this English statement, displayed equation where present and stated hypotheses against these source locations: Discrete memoryless capacity region and independent conditional inputs; DM-MAC pp. 28–35, broadcast pp. 38–47, distortion pp. 48–52, Wyner–Ziv/Slepian–Wolf pp. 53–59, relay pp. 78–94, multicast pp. 100–116. The check is bounded to the recorded claims; no complete proof reconstruction, software proof replay or universal literature completeness is claimed.
2026-10-10 · Author source-body/statement/equation/domain check, with graph associations scoped individually. Separate independent content/source/inventory review is required before branch closure.
Entry details
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- Postgraduate & research reference