Chapter Summary and Book Conclusion

Chapter Summary and Book Conclusion

Key Points

• 1.

  Open Problem 1: Coded placement. MAN is optimal under uncoded placement (YMA 2018). Under coded placement, MAN is achievable but possibly not optimal. Gap at most factor 2; conjectured zero. Most important open problem.

• 2.

  Open Problem 2: Heterogeneous caches. Constant-factor bounds known; tight rate characterization open. Memory sharing works practically but is not optimal.

• 3.

  Open Problem 3: Finite blocklength. For small files or large $K$, MAN rate not achievable. PDAs (Ch 14) mitigate. FB capacity characterization open.

• 4.

  Open Problem 4: Integration with modern architectures. Open RAN, cell-free Massive MIMO, NTN, AI/ML workloads — each raises new design questions.

• 5.

  CommIT decade (2014-2024) has shaped the field. MAN, multi-antenna, D2D, cloud-RAN, privacy, multi-rate, heterogeneous, ISAC — all major branches have CommIT contributions.

• 6.

  Research horizon: 2025-2030. Commercial deployment pivots on 6G standards. Standards-ready coded-caching primitives enable mass deployment. Without them, the field remains theoretically elegant but practically niche.

• 7.

  Book conclusion. Coded caching is a mature research area with deep results, a clear central insight (memory → bandwidth via coding), and concrete open problems. The next decade decides whether it graduates from brilliant theory to deployed practice.