LTE RRCConnectionReestablishment procedure

The purpose of RRCConnectionReestablishment procedure is to re-establish the RRC connection, which involves the resumption of SRB1 operation, the re-activation of security and the configuration of only the PCell.

E-UTRAN applies the procedure as follows:
1. To reconfigure SRB1 and to resume data transfer only for this RB
2. To re-activate AS security without changing algorithm.

The UE only initiate the procedure when AS security has been activated. Following conditions has to be met
1. Detect radio link failure. Upon receiving N310 consecutive "out-of-sync" indications for the PCell from lower layers while neither T300, T301, T304 nor T311 is running. (UE shall start timer T310)
2. Detect radio link failure. Upon receiving N313 consecutive "out-of-sync" indications for the PCell from lower layers while T307 is not running. (UE shall start timer T313)
3. Upon handover failure. 36.331 5.3.5.6
4. Upon mobility from E-UTRA failure. 36.331 5.4.3.5
5. Upon integrity check failure indication from lower layers
6. Upon an RRC connection reconfiguration failure. 36.331 5.3.5.5

Upon initiation of the procedure, the UE shall:
1. Stop timer T310, if running
2. Stop timer T312, if running
3. Stop timer T313, if running
4. Stop timer T307, if running
5. Start timer T311
6. Suspend all RBs except SRB0
7. Reset MAC
8. Release the MCG SCell(s), if configured. 36.331 5.3.10.3a
9. Apply the default physical channel configuration as specified in 36.331 9.2.4
10. For the MCG, apply the default semi-persistent scheduling configuration as specified in 9.2.3
11. For the MCG, apply the default MAC main configuration as specified in 9.2.2
12. Release powerPrefIndicationConfig, if configured and stop timer T340, if running
13. Release reportProximityConfig and clear any associated proximity status reporting timer.
14. Release obtainLocationConfig, if configured
15. Release idc-Config, if configured.
16. Release measSubframePatternPCell, if configured
17. Release the entire SCG configuration, if configured, except for the DRB configuration (as configrued by drb-ToAddModListSCG)
18. Release naics-Info for the PCell, if configured
19. Release the RN subframe, if connected as RN and configured with an RN subframe configuration.
20. Perform cell selection process as specified in 36.304

Upon receiving the RRCConnectionReestablishmentReject message, the UE shall perform the action upon leaving RRC_CONNECTED as specified in 5.3.12 with release cause 'RRC connection failure'.

LTE system information block introduction (SIB3)

SIB3 IE introduction. SIB3 contains mainly cell re-selection information for intra-frequency.

(1) IE cellReselectionInfoCommon
IE q-Hyst, this value is in unit of dB, it is Qhyst in 36.304. This value is applied when UE detected itself in Medium-mobility or High-mobility state (Only if TCRmax, NCR_M, NCR_H and TCRmaxhyst is sent in SIB3). The criteria of detecting Medium-mobility state or High-mobility state is as follows (Quoted from 36.304 5.2.4.3):

Medium-mobility state criteria:

• If number of cell reselections during time period TCRmax exceeds NCR_M, and not exceed NCR_H

High-mobility state criteria:

• If number of cell reselections during time period TCRmax exceeds NCR_H

The UE shall not count consecutive reselections between same two cells into mobility state detection criteria if same cell is reselected just after one other reselection.

(2) IE cellReselectionServingFreqInfo

IE s-NonIntraSearch = SnonIntraSearchP. If the field s-NonIntraSearchP is present, the UE applies the value of s-NonIntraSearchP instead. Otherwise if neither s-NonIntraSearch nor s-NonIntraSearchP is present, the UE applies the (default) value of infinity for SnonIntraSearchP

IE threshServingLow

measurementGap calculation

measurementGap is configured to UE for measuring different frequencies. Following notes should be considered when working with measurementGap.

1. Normal measurementGap configuration. Fully length is taken by UE.  

GapOffset	14
MGRP	40
MGL	6
T	4
GapSubframe	4

For above configuration, measurementGap will look like following every 40ms. 

		subframe
SFN		0	1	2	3	4	5	6	7	8	9
0	-	-	-	-	-	-	-	-	-	-	-
1	GAP	-	-	-	-	G	G	G	G	G	G
2	-	-	-	-	-	-	-	-	-	-	-
3	-	-	-	-	-	-	-	-	-	-	-

2. Special measurementGap configuration. Fully length is taken by UE. 

GapOffset	29
MGRP	40
MGL	6
T	4
GapSubframe	9

For above configuration, measurementGap will look like following every 40ms. Note the shortened length of measurementGap of 1ms instead of 6ms as parameter indicated. 

		subframe
SFN		0	1	2	3	4	5	6	7	8	9
0	-	-	-	-	-	-	-	-	-	-	-
1	-	-	-	-	-	-	-	-	-	-	-
2	GAP	-	-	-	-	-	-	-	-	-	G
3	GAP	G	G	G	G	G	-	-	-	-	-

Relation between "DL Rate Matched Bits Sum" and Reference Signal

Following rules applied to subframes that are not subframe0 and subframe5 (subframe9 without paging)

For normal cyclic shift (7 OFDM symbols in a slot)
antenna port 0 and antenna port 1 occupied REs in 1 PRB for 1 codeword excluding PDCCH and PCFICH is 12 REs
antenna port 2 and antenna port 3 occupied REs in 1 PRB for 1 codeword excluding PDCCH and PCFICH is 8 REs
antenna port 5 occupied REs in 1 PRB for 1 codeword is 12 REs
antenna port 15 and antenna port 16 occupied REs in 1 PRB is 2 REs
antenna port 7 and antenna port 8 occupied REs in 1 PRB is 12 REs

For TM3 2x2 10MHz CFI=1
Number of available REs is 7200
1 codeword with 64QAM modulation, bits rate is 7200 * 6 = 43200 bits/msec
2 codeword with 64QAM modulation, bits rate is 7200 * 6 * 2 = 86400 bits/msec

For TM4 4x2 (4x4) 10MHz CFI=1
Number of available REs is 7200 - 400 = 6800
1 codeword with 64QAM modulation, bits rate is 6800 * 6 = 40800 bits/msec
2 codeword with 64QAM modulation, bits rate is 6800 * 6 * 2 = 81600 bits/msec

For TM9 2x2 10MHz CFI=1
For non-CSI-RS subframes
Number of available REs is 7200 - 600 = 6600
1 codeword with 64QAM modulation, bits rate is 6600 * 6 = 39600 bits/msec
2 codeword with 64QAM modulation, bits rate is 6600 * 6 * 2 = 79200 bits/msec

For CSI-RS subframes
Number of available REs is 7200 - 600 - 100 = 6500
1 codeword with 64QAM modulation, bits rate is 6500 * 6 = 39000 bits/msec
2 codeword with 64QAM modulation, bits rate is 6500 * 6 * 2 = 78000 bits/msec

For TM9 4x2 (4x4) 10MHz CFI=1
For non-CSI-RS subframes
Number of available REs is 7200 - 600 - 400 = 6200
1 codeword with 64QAM moudulation, bits rate is 6200 * 6 = 37200 bits/msec
2 codeword with 64QAM modulation, bits rate is 6200 * 6 * 2 = 74400 bits/msec

For CSI-RS subframes
Number of available REs is 7200 - 800 - 400 - 100 = 6100
1 codeword with 64QAM moudulation, bits rate is 6100 * 6 = 36600 bits/msec
2 codeword with 64QAM modulation, bits rate is 6100 * 6 * 2 = 73200 bits/msec


For subframe0 and subframe5, PBCH, PSS and SSS would take away some REs.

PBCH would occupy extra 72 * 4 - (4 * 6) - (4 * 6)= 240REs
PSS and SSS would occupy extra 72 * 2 = 144REs

Note: for subframe0, TM3 2x2 total available REs for PDSCH is equal to 7200 - 240 - 144 -24 = 6792REs