noiseless-multicast-network

Noiseless single-source multicast network

One source sends a common message to every designated receiver in a finite directed acyclic network.

Broadcast Finite alphabet Capacity Single-letter characterization

Channel and question

Input
Binary packets on directed links with specified nonnegative rate budgets.
Output
Incoming packets at each designated sink.
Law
Every link transmits its packet without error. Nodes process incoming packets in topological order.
Quantity
Noiseless single-source multicast network capacity \(C\), measured in bits per channel use.

Criterion. Vanishing average block error, with the constraints specified in the model.

  • The finite vertex order is acyclic and vertex zero is the unique source.
  • There is at least one designated sink and the source is not a sink.
  • An n-use code sends exactly floor(n r_e) bits on edge e. Packet lengths and schedules convey no information.
  • Only the source observes the message. Other nodes use only incoming packets.
  • All designated sinks decode the same uniform message.

Current status

\[C=\min_{t\in T}\min_{S:0\in S,\ t\notin S}\sum_{e\in\delta^+(S)}r_e\]
Known results and bounds for Noiseless single-source multicast network
ResultRelationMethodYear
Exact\(C=\min_{t\in T}\min_{S:0\in S,\ t\notin S}\sum_{e\in\delta^+(S)}r_e\)Linear network coding and a cut-set converse.2000

Formal verification

Lean coverageFormally stated

Concrete operational definitions and admitted research statements are present. Existing proofs are preserved. New statements require mathematical review and proof completion.

Claims

  • Single-source topological processing on a finite noiseless acyclic network.
    operational-capacity · exact capacity · solved · Formally stated · v1
Lean declarations (1)

References

  1. Rudolf Ahlswede, Ning Cai, Shuo-Yen Robert Li, and Raymond W. Yeung (2000). Network Information Flow. IEEE Transactions on Information Theory. DOI 10.1109/18.850663.

Discussion

Related problems

One encoder sends the same message to every receiver in a fixed finite family.

Broadcast Finite alphabet Discrete memoryless Capacity Exact Single-letter characterization
Solved \(C_{\mathrm{common}}=\max_{P_X}\min_{j\in\mathcal J}I(X;Y_j)\)

The three-input Blackwell channel is a concrete nondegraded deterministic broadcast channel with an exact entropy capacity region.

Broadcast Finite alphabet Discrete memoryless Asymmetric Capacity region Exact Single-letter characterization
Solved \(R_1\le H(Y_1),\quad R_2\le H(Y_2),\quad R_1+R_2\le H(Y_1,Y_2)\)

An iid channel state is revealed causally to the encoder but not to the decoder.

Point-to-point Finite alphabet Discrete memoryless Causal state information Side information Capacity Exact Single-letter characterization
Solved \(C_{\mathrm{causal}}=\max_{P_U,\,x=f(U,S),\,U\perp S} I(U;Y)\)

The entire iid state sequence is known noncausally to the encoder but not the decoder.

Point-to-point Finite alphabet Discrete memoryless Noncausal state information Side information Capacity Exact Single-letter characterization
Solved \(C_{\mathrm{GP}}=\max_{P_{U|S},\,x=f(U,S)}\bigl[I(U;Y)-I(U;S)\bigr]\)