tag:blogger.com,1999:blog-1329449351744515518.post8093320236308745950..comments2023-09-16T01:28:38.178-07:00Comments on Wired n Wireless: LTE HandoversSantosh Dornalhttp://www.blogger.com/profile/08888256274707899999noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-1329449351744515518.post-63898027925082659442010-06-08T07:30:04.760-07:002010-06-08T07:30:04.760-07:00LTE intra-RAT handovers between BS are
qualified b...LTE intra-RAT handovers between BS are<br />qualified by the following properties :<br /><br />1. BS have an X2 connection<br />2. The MME serving the BS<br />3. The SGW serving the BS<br /><br />So, with #1 = Yes / No, #2/#3 =<br />Same/Different, you have 2 x 2 x 2 = 8<br />different scenarios :<br /><br />T1. (Yes,Same,Same)<br />T2. (No,Same,Same)<br />T3. (Yes,Different,Same)<br />T4. (No,Different,Same)<br />T5. (Yes,Same,Different)<br />T6. (No,Same,Different)<br />T7. (Yes,Different,Different)<br />T8. (No,Different,Different)<br /><br /><br />Your diagrams appear to cover the<br />following : T1, T6, T8, T4Moh Yannoreply@blogger.comtag:blogger.com,1999:blog-1329449351744515518.post-36027458006046958222009-09-02T04:26:24.427-07:002009-09-02T04:26:24.427-07:00Hi Kaushik
Considering an X2 based handover where...Hi Kaushik<br /><br />Considering an X2 based handover where both target and source eNB are communicating using X2AP, RRC Reconfig command will be sent by source eNB to UE only when Source eNB receives handover request ack from target eNB. Once UE receives the RRC reconfig command it will directly establish or modify the RRC connections to the target eNB. I believe same is the case when MME and SGW is changed. After UE established the RRC connection with target eNB it can start sending the data. Target eNB will buffer the data untill the EPS bearers are established/modified accordingly. <br /><br />And I guess there will be only one RRC connection in UE. This will be modified or created again when UE enter new eNB. 3GPP TS 36.300. Refer to section 10.1.2. <br /><br />Thanks, SantoshSantosh Dornalhttps://www.blogger.com/profile/08888256274707899999noreply@blogger.comtag:blogger.com,1999:blog-1329449351744515518.post-83103592215259662632009-09-02T03:38:47.908-07:002009-09-02T03:38:47.908-07:00could you please tell me what happen to RRC connec...could you please tell me what happen to RRC connection in the target enodeB in case where the MME is also changing. Does the UE make a RRC connection and default radio bearer as soon as it detects the second enodeB or it makes this connection after receiving Hadnover command. in this case, is there a possibility that two RRC connection exists in the UE simultaneously?<br /><br />Thanks <br />KaushikAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-1329449351744515518.post-85672367632784583302009-09-02T00:11:20.814-07:002009-09-02T00:11:20.814-07:00Yes! I will update the post with above scenario to...Yes! I will update the post with above scenario tonight. Thanks Kostubh!Santosh Dornalhttps://www.blogger.com/profile/08888256274707899999noreply@blogger.comtag:blogger.com,1999:blog-1329449351744515518.post-23412731937805404862009-09-02T00:07:18.957-07:002009-09-02T00:07:18.957-07:00I think the below scenario is also possible:
UE -...I think the below scenario is also possible:<br /><br />UE --- eNB_1 --- MME_1 --- S-GW_1 --- P-GW<br /><br />moved to new eNB2 which is served by new MME_2 but old S-GW_1:<br /><br />UE --- eNB_2 --- MME_2 --- S-GW_1 --- P-GWKostubh Sharmanoreply@blogger.com