Prerequisites & Notation

Before You Begin

This chapter treats multi-transmitter coded caching — multiple base stations cooperating to serve users with coded content. Prerequisites include the MAN scheme, multi-antenna coded caching, and the C-RAN architecture of Chapter 8.

The MAN scheme and the rate formula (Ch 2)(Review ch02)
Self-check: Can you state the MAN placement and delivery for integer $t$ ?
Multi-antenna coded caching and DoF = $t + L$ (Ch 5)(Review ch05)
Self-check: Can you sketch the Lampiris-Caire scheme?
Cloud-RAN and NDT framework (Ch 8)(Review ch08)
Self-check: Can you state the NDT upper bound?
Cooperative MIMO / CoMP transmission(Review ch17)
Self-check: How does cooperative MIMO improve throughput compared to single-cell MU-MIMO?
Cell-free massive MIMO basics(Review ch11)
Self-check: What is the difference between cellular and cell-free massive MIMO?
Shared vs dedicated resources
Self-check: In what sense does a shared cache 'substitute' for a dedicated cache per user?

Notation for This Chapter

Symbols for multi-server / multi-base-station coded caching.

Symbol	Meaning	Introduced
$S$	Number of cooperating servers (base stations / transmitters)	s01
$K$	Number of users	s01
$M$	Per-user cache size in file units (dedicated cache model)	s01
$K_s$	Number of users per cache (shared cache model): $K_s = K/L$ where $L$ is the number of caches	s02
$L$	Per-server transmit antennas	s01
$\mathbf{h}_{k,i}$	Channel vector from server $i$ to user $k$	s01
$t$	Caching gain $t = KM/N$	s01

← Ch 8 The Multi-Server Coded Caching Model