LTE radio resources

LTE radio links

PDCCH construction
Control Channel Element (36.213 §9)
Wireless downloads
Resource grid (S.Dhagle)
3GPP Specification Release version matrix
USIM 31.102
ISIM 31.103
CSIM : 3GPP2 C.S0065

System Information (36.331 Rel 13 Mar 2016)

SIB Description Comment
MIB Downlink channel bandwidth, PHICH config SFN
1 PLMN, TAC, Cell Id, access restrictions, q-RxLevMin, frequency band, MFBI Scheduling of other SIBs
1 BR Bandwidth Reduced, limited channel bandwidth of 6 PRBs eMTC (enhanced Machine Type Communications)
2 Common radio resource config, access class barring, MBSFN config UL frequency and bandwidth
3 Cell re-selection common information
4 Cell re-selection information for intra-frequency neighbouring cells Black cell list
5 Cell re-selection information for inter-frequency neighbouring cells
6 Cell re-selection information for UTRA
7 Cell re-selection information for GERAN
8 Cell re-selection information for CDMA2000
9 Home eNodeB name
10 ETWS (Earthquake and Tsunami Warning System) Primary notification
11 ETWS Secondary notification
12 CMAS (Commercial Mobile Alert Service) notification
13 MBMS control information associated with one or more MBSFN areas
14 EAB (Extended access class barring) parameters
15 MBMS Service Area Identities (SAI), neighbouring carrier frequencies
16 GPS time and Coordinated Universal Time (UTC)
17 Traffic steering between E-UTRAN and WLAN
18 Sidelink UE information, sidelink direct communication related resource
19 Sidelink UE information, sidelink direct discovery related resource
20 Control information associated transmission of MBMS using SC-PTM
21 V2X

Standardized QoS Class Identifier (23.203 Rel 13 Mar 2016)

Policy and charging control architecture

QCI Traffic Class Priority Packet delay
budget
Packet error
loss rate
Resource type Example Services
1 Conversational 2 100 ms 10-2 GBR Conversational Voice
2 Conversational 4 150 ms 10-3 GBR Conversational Video (Live Streaming)
3 Streaming 3 50 ms 10-3 GBR Real Time Gaming
4 Streaming 5 300 ms 10-6 GBR Non-Conversational Video (Buffered Streaming)
65 0.7 75 ms 10-2 GBR Mission Critical user plane Push To Talk voice
(e.g., MC-PTT)
66 2 100 ms 10-2 GBR Non-Mission-Critical user plane Push To Talk voice
5 Interactive 1 100 ms 10-6 Non-GBR IMS Signalling
6 Interactive 6 300 ms 10-6 Non-GBR Video (Buffered Streaming)
TCP-based (e.g., www, e-mail, chat, ftp,
p2p file sharing, progressive video, etc.)
7 Interactive 7 100 ms 10-3 Non-GBR Voice,
Video (Live Streaming)
Interactive Gaming
8 Interactive 8 300 ms 10-6 Non-GBR Video (Buffered Streaming)
TCP-based (e.g., www, e-mail, chat, ftp,
p2p file sharing, progressive video, etc.)
9 Background 9 300 ms 10-6 Non-GBR
69 0.5 60 ms 10-6 Non-GBR Mission Critical delay sensitive signalling
(e.g., MC-PTT signalling)
70 5.5 200 ms 10-6 Non-GBR Mission Critical Data
(e.g. example services are the same as QCI 6/8/9)

GBR
Guaranteed Bitrate Resources
QCI
QoS Class Identifier
MC-PTT
Mission Critical - Push To Talk

Timing Advance Command

A device receives a timing advance command from the network and adjusts uplink timing for PUCCH / PUSCH / SRS transmission

36.211 Frame structure

Basic time unit : Ts = 1 / (15000 x 2048) seconds
Radio frame duration : Tf = (150 x 2048) x Ts = 307200 x Ts = 10 ms
NTA = timing offset between uplink and downlink radio frames at the UE, expressed in units of Ts

36.321 MAC Timing Advance Command

Distance between a device and the network antenna :
A timing advance of one Ts is equivalent to a distance of (3 x 108 x 1 / (15000 x 2048)) / 2 = 4.89 m
Distance = propagation speed (light speed) x one Ts delay / 2 (downlink path + uplink path)

36.213 Transmission timing adjustments

Initial absolute Random Access Response MAC payload (11 bits) TA range = 0, 1, 2,..., 1282

Random Access Response NTA = TA x 16. Timing adjustment is always positive
Example : TA = 1 then NTA = 1 x 16 Ts. Distance equals 16 x 4.89 m = 78.12 m
Distance maximum between a device and the network antenna = 1282 x 78.12 m = 100.156 km (62.23 mi)

Periodic relative Timing Advance Command MAC Control Element (6 bits) TA range = 0, 1, 2,..., 63

Timing Advance Command NTA,new = NTA,old + (TA - 31) x 16. Timing adjustment can be negative, null or positive
Example : TA = 30 then NTA,new = NTA,old + (30 - 31) x 16 Ts = NTA,old - 1 x 16 Ts. Distance variation equals -1 x 16 x 4.89 m = - 78.12 m
Distance variation maximum = - 31 x 16 x 4.89 m = - 2.42 km or + 32 x 16 x 4.89 m = + 2.5 km (1.55 mi)

36.214 Timing advance (TADV)

TAdvType1 = eNB Rx–Tx time difference + UE Rx–Tx time difference
TAdvType2 = eNB Rx–Tx time difference
eNB Rx–Tx time difference = eNb processing delay
UE Rx–Tx time difference = DL propagation delay + UE processing delay + UL propagation delay
TAdvType1 = eNb processing delay + (DL+UL) propagation delay + UE processing delay
TAdvType2 = eNb processing delay

36.455 LPPa TAdvType1 index range = 0..7690 (36.133 §10.3 value range = 0..49232 Ts)
36.355 LPP ue-RxTxTimeDiff index range = 0..4095 (36.133 §10.3 value range = 0..20472 Ts)

36.455 LPPa TAdvType2 index range = 0..7690 (36.133 §10.3 value range = 0..49232 Ts)