Bandwidth part — A configured window of the carrier a device actually uses

5G Systems Notes · Concept map · Bandwidth part Route · Hierarchy · Index · All concepts · Hub

The grid and its units

Where it sits

Sits atLevel 6 of the hierarchy · The grid and its units · explained
Also writtenBWP
Learn firstResource block · Point A — 9 concepts in the full chain, see the paths
UnlocksCORESET · Carrier aggregation
Primary clauseTS 38.213 §12, TS 38.211 §4.4.5
Used innr-frame-structure 15 · nr-pdsch 5
Scanned from the notes at page load and joined with terms.json; nothing on this card is typed by hand.

What it is

A bandwidth part is a configured window of the carrier that a device actually uses — a contiguous set of common resource blocks at one numerology.

It exists so a device need not receive the whole carrier. A 100 MHz carrier is expensive to receive continuously; a device given a 20 MHz bandwidth part runs a narrower filter and a smaller FFT, and saves power in proportion.

Four numbers define one: a starting common resource block, a size, a numerology and a cyclic prefix. Up to four may be configured per direction, and one is active at a time; switching is signalled in the DCI.

Read on

The full treatment is in nr-frame-structure — this page is the definition and the map reference; that note is where the subject is actually developed.

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Before this concept, the hierarchy says to learn the following — the full chain, in order:

To understand Bandwidth part (level 6) you first need 9 other concepts. Read them in this order — everything on one line can be read in any order, but no line before the one above it:
Level Learn these
0 Subcarrier
1 OFDM
2 OFDM symbol
3 Cyclic prefix · Resource element · Slot
4 Numerology · Resource block
5 Point A
Immediately before Bandwidth part: Resource block, Point A.
Keep going — where this sits on the route
◀5G AKAstep 58 · level 5
Step 59 of 118level 6 · The grid and its units
Transport channelstep 60 · level 6▶
Level 6 → 7 · this unlocks
CORESET · Carrier aggregation
↳ all 13 concepts at level 7 · level 6 in full · the whole route
The route is every concept in the folder ordered by level, so nothing here needs anything after it. Computed at page load from terms.json; the same numbering as the route page.
5G Systems Notes · Concept map · Bandwidth part Top · Concept map · Hub