eUTRAN to UTRAN Iu mode Inter RAT RA T handover h andover General information Pre-conditions: •
The UE is in ECM-CONNECTED state (E-UTRAN mode).
If emerenc! "earer ser#ices are onoin for an UE$ hando#er to the taret RNC is %erformed inde%endent of the &ando#er Restriction 'ist. The N ch ec*s$ as %art of the Ro+tin Area U%date in the e,ec+tion %hase$ if the hando#er is to a restricted area and if so N deacti#ate the non-emerenc! PDP conte,t.
Preparation phase
i. . E-UTRAN to UTRAN I+ mode Inter RAT &O %re%aration %hase. Step 1. The so+rce eNode/ decides to initiate an Inter-RAT Inter-RAT hando#er to the taret access net0or*$ UTRAN I+ mode. At this %oint "oth +%1in* and do0n1in* +ser data is transmitted #ia the fo11o0in: /earer(s) "et0een UE and so+rce eNode/$ TP t+nne1(s) "et0een so+rce eNode/$ er#in 2 and PDN 2.
If the UE has an onoin emerenc! "earer ser#ice the so+rce eNode/ sha11 not initiate P hando#er to a UTRAN ce11 that is not IM #oice ca%a"1e. Step 2. The so+rce eNode/ sends a &ando#er Re3+ired (AP Ca+se$ Taret RNC Identifier$ C ID$ C access mode$ o+rce eNode/ Identifier$ o+rce to Taret Trans%arent Container) messae to the so+rce MME to re3+est the CN to esta"1ish reso+rces in the taret RNC$ taret N and the er#in 2. The "earers that 0i11 "e s+"4ect to data for0ardin (if an!) are identified "! the taret N in a 1ater ste% (see step 7 "e1o0). 2hen the taret ce11 is a C ce11 or a h!"rid ce11$ the so+rce eNode/ sha11 inc1+de the C ID of the taret ce11. If the taret ce11 is a h!"rid ce11$ the C access mode sha11 "e indicated. Step 3. The so+rce MME determines from the 5Taret RNC Identifier5 IE that the t!%e of hando#er is IRAT &ando#er to UTRAN I+ mode. The o+rce MME initiates the &ando#er reso+rce a11ocation %roced+re "! sendin a or0ard Re1ocation Re3+est (IMI$ Taret Identification$ C ID$ C Mem"ershi% Indication$ MM Conte,t$ PDN Connections$ MME T+nne1 End%oint Identifier for Contro1 P1ane$ MME Address for Contro1 %1ane$ o+rce to Taret Trans%arent Container$ RAN Ca+se$ M Info Chane Re%ortin Action (if a#ai1a"1e)$ C Information Re%ortin Action (if a#ai1a"1e)$ UE Time 6one$ IR +%%orted) messae to the taret N. The information IR +%%orted is indicated if the so+rce MME and associated er#in 2 are ca%a"1e to acti#ate IR for the UE. 2hen IR is acti#ated the messae sho+1d "e sent to the N that maintains IR for the UE 0hen this N is ser#in the taret identified "! the Taret Identification. This messae inc1+des a11 PDN Connections acti#e in the so+rce s!stem and for each PDN Connection inc1+des the associated APN$ the address and the +%1in* T+nne1 end%oint %arameters of the er#in 2 for contro1 %1ane$ and a 1ist of EP /earer Conte,ts. RAN Ca+se indicates the AP Ca+se as recei#ed from so+rce eNode/. The so+rce MME sha11 %erform access contro1 "! chec *in the UE5s C s+"scri%tion 0hen C ID is %ro#ided "! the so+rce eNode/. If there is no s+"scri%tion data for this C ID or the C s+"scri%tion is e,%ired$ and the taret ce11 is a C ce11$ the so+rce MME sha11 re4ect the hando#er 0ith an a%%ro%riate ca+se. The so+rce MME inc1+des the C ID in the or0ard Re1ocation Re3+est 0hen the taret ce11 is a C ce11 or h!"rid ce11. 2hen the taret ce11 is a h!"rid ce11$ the C Mem"ershi% Indication indicatin 0hether the UE is a C mem"er sha11 "e inc1+ded in the or0ard Re1ocation Re3+est messae. The taret N ma%s the EP "earers to P DP conte,ts -to- and ma%s the EP /earer 7o %arameter #a1+es of an EP "earer to the Re1ease 88 7o %arameter #a1+es of a "earer conte,t. Prioriti9ation of PDP Conte,ts is %erformed "! the taret core net0or* node$ i.e. taret N. The MM conte,t contains sec+rit! re1ated information$ e.. s+%% orted ci%herin a1orithms The taret N sha11 determine the Ma,im+m APN restriction "ased on the APN Restriction of each "earer conte,t in the or0ard Re1ocation Re3+est$ and sha11 s+"se3+ent1! store the ne0 Ma,im+m APN restriction #a1+e. Step 4. The taret N determines if the er#in 2 is to "e re1ocated$ e..$ d+e to P'MN chane. If the er#in 2 is to "e re1ocated$ the taret N se1ects the taret er#in 2$ and sends a Create ession Re3+est messae (IMI$ N T+nne1 End%oint Identifier for Contro1 P1ane$ N Address for Contro1 %1ane$ PDN 2 address(es) for +ser %1ane$ PDN 2 U' TEID(s) for +ser %1ane$ PDN 2 address(es) for contro1 %1ane$ and PDN 2 TEID(s) for contro1 %1ane$ the Protoco1 T!%e o#er ;<$ er#in Net0or*) %er PDN connection to the taret er#in 2. The Protoco1 T!%e o#er ;< is %ro#ided to er#in 2 0hich %rotoco1 sho+1d "e +sed o#er ;< interface.
The taret N esta"1ishes the EP /earer conte,t(s) in the indicated order. The N deacti#ates$ as %ro#ided in step 7 of the e,ec+tion %hase$ the EP /earer conte,ts 0hich cannot "e esta"1ished. Step 4a. The taret er#in 2 a11ocates its 1oca1 reso+rces and ret+rns a Create ession Res%onse (er#in 2 address(es) for +ser %1ane$ er#in 2 U' TEID(s) for +ser %1ane$ er#in 2 Address for contro1 %1ane$ er#in 2 TEID for contro1 %1ane) messae to the taret N. Step 5. The taret N re3+ests the taret RNC to esta"1ish the radio net0or* reso+rces (RA/s) "! sendin the messae Re1ocation Re3+est (UE Identifier$ Ca+se$ CN Domain Indicator$ Interit! %rotection information (i.e. I= and a11o0ed Interit! Protection a1orithms)$ Encr!%tion information (i.e. C= and a11o0ed Ci%herin a1orithms)$ RA/ (Radio Access /earer) to "e set+% 1ist$ C ID$ C Mem"ershi% Indication$ o+rce RNC to Taret RNC Trans%arent Container$ er#ice &ando#er re1ated information). If the Access Restriction is %resent in the MM conte,t$ the er#ice &ando#er re1ated information sha11 "e inc1+ded "! the taret N for the Re1ocation Re3+est messae in order for RNC to restrict the UE in connected mode to hando#er to the RAT %rohi"ited "! the Access Restriction. or each RA/ re3+ested to "e esta"1ished$ RA/s To /e et+% sha11 contain information s+ch as RA/ ID$ RA/ %arameters$ Trans%ort 'a!er Address$ and I+ Trans%ort Association. The RA/ ID information e1ement contains the NAPI #a1+e$ and the RA/ %arameters information e1ement i#es the 7o %rofi1e. The Trans%ort 'a!er Address is the er#in 2 Address for +ser %1ane (if Direct T+nne1 is +sed) or the N Address for +ser % 1ane (if Direct T+nne1 is not +sed)$ and the I+ Trans%ort Association corres%onds to the +%1in* T+nne1 End%oint Identifier Data in er#in 2 or N res%ecti#e1!. Ci%herin and interit! %rotection *e!s are sent to the taret RNC to a11o0 data transfer to contin+e in the ne0 RAT;mode taret ce11 0itho+t re3+irin a ne0 A=A (A+thentication and =e! Areement) %roced+re. Information that is re3+ired to "e sent to the UE (either in the Re1ocation Command messae or after the hando#er com%1etion messae) from RRC in the taret RNC sha11 "e inc1+ded in the RRC messae sent from the taret RNC to the UE #ia the trans%arent container. The Taret N sha11 inc1+de the C ID and C Mem"ershi% Indication 0hen %ro#ided "! the so+rce MME in the or0ard Re1ocation Re3+est messae. In the taret RNC radio and I+ +ser %1ane reso+rces are reser#ed for the acce%ted RA/s. Ca+se indicates the RAN Ca+se as recei#ed from so+rce MME. The o+rce RNC to Taret RNC Trans%arent Container inc1+des the #a1+e from the o+rce to Taret Trans%arent Container recei#ed from the so+rce eNode/. If the taret ce11 is a C ce11$ the taret RNC sha11 #erif! the C ID %ro#ided "! the taret N$ and re4ect the hando#er 0ith an a%%ro%riate ca+se if it does not match the C ID for the taret ce11. If the taret ce11 is in h!"rid mode$ the taret RNC ma! +se the C Mem"ershi% Indication to %erform differentiated treatment for C and non-C mem"ers. Step 5a. The taret RNC a11ocates the reso+rces and ret+rns the a%%1ica"1e %arameters to the taret N in the messae Re1ocation Re3+est Ac*no01ede (Taret RNC to o+rce RNC Trans%arent Container$ RA/s set+% 1ist$ RA/s fai1ed to set+% 1ist). U%on sendin the Re1ocation Re3+est Ac*no01ede messae the taret RNC sha11 "e %re%ared to recei#e do0n1in* TP PDUs from the er#in 2$ or Taret N if Direct T+nne1 is not +sed$ for the acce%ted RA/s. Each RA/s set+% 1ist is defined "! a Trans%ort 'a!er Address$ 0hich is the taret RNC Address
for +ser data$ and the I+ Trans%ort Association$ 0hich corres%onds to the do0n1in* T+nne1 End%oint Identifier for +ser data. An! EP /earer conte,ts for 0hich a RA/ 0as not esta"1ished are maintained in the taret N and the UE. These EP /earer conte,ts sha11 "e deacti#ated "! the taret N #ia e,%1icit M %roced+res +%on the com%1etion of the ro+tin area +%date (RAU) %roced+re. Step 6. If 5Indirect or0ardin5 and re1ocation of er#in 2 a%%1! and Direct T+nne1 is +sed the taret N sends a Create Indirect Data or0ardin T+nne1 Re3+est messae (Taret RNC Address and TEID(s) for D' data for0ardin) to the er#in 2. If 5Indirect or0ardin5 and re1ocation of er#in 2 a%%1! and Direct T+nne1 is not +sed$ then the taret NN Address and TEID(s) for D' data for0ardin) to the er#in 2. Indirect for0ardin ma! "e %erformed #ia a er#in 2 0hich is different from the er#in 2 +sed as the anchor %oint for the UE. Step 6a. The er#in 2 ret+rns a Create Indirect Data or0ardin T+nne1 Res%onse (Ca+se$ er#in 2 Address(es) and er#in 2 D' TEID(s) for data for0ardin) messae to the taret N. Step 7. The taret N sends the messae or0ard Re1ocation Res%onse (Ca+se$ N T+nne1 End%oint Identifier for Contro1 P1ane$ N Address for Contro1 P1ane$ Taret to o+rce Trans%arent Container$ Ca+se$ RA/ et+% Information$ Additiona1 RA/ et+% Information$ Address(es) and TEID(s) for User Traffic Data or0ardin$ er#in 2 chane indication) to the so+rce MME. er#in 2 chane indication indicates a ne0 er#in 2 has "een se1ected. The Taret to o+rce Trans%arent Container contains the #a1+e from the Taret RNC to o+rce RNC Trans%arent Container recei#ed from the taret RNC. The IE 5Address(es) and TEID(s) for User Traffic Data or0ardin5 defines the destination t+nne11in end%oint for data for0ardin in taret s!stem$ and it is set as fo11o0s: •
If 5Direct or0ardin5 a%%1ies$ or if 5Indirect or0ardin5 and no re1ocation of er#in 2 a%%1! and Direct T+nne1 is +sed$ then the IE 5Address(es) and TEID(s) for User Traffic Data or0ardin5 contains the addresses and TP-U t+nne1 end%oint %arameters to the Taret RNC recei#ed in step 5a.
•
If 5Indirect or0ardin5 and re1ocation of er#in 2 a%%1!$ then the IE 5Address(es) and TEID(s) for User Traffic Data or0ardin5 contains the addresses and D' TP-U t+nne1 end%oint %arameters to the er#in 2 recei#ed in ste% >. This is inde%endent from +sin Direct T+nne1 or not.
•
If 5Indirect or0ardin5 a%%1ies and Direct T+nne1 is not +sed and re1ocation of er#in 2 does not a%%1!$ then the IE 5Address(es) and TEID(s) for User Traffic Data or0ardin5 contains the D' TP-U t+nne1 end%oint %arameters to the Taret N.
Step 8. If ?Indirect or0ardin? a%%1ies$ the o+rce MME sends the messae Create Indirect Data or0ardin T+nne1 Re3+est (Address(es) and TEID(s) for Data or0ardin (recei#ed in step 7))$ EP /earer ID(s)) to the er#in 2 +sed for indirect for0ardin. Indirect for0ardin ma! "e %erformed #ia a er#in 2 0hich is different from the er#in 2 +sed as the anchor %oint for the UE. Step 8a. The Serving 2 returns the forwarding parameters by sending the
message Create Indirect Data Forwarding Tunnel Response (Cause, Serving
2 ddress(es! and TEID(s! for Data Forwarding!" If the Serving 2 doesn#t
support data forwarding, an appropriate cause value shall be returned and the Serving 2 ddress(es! and TEID(s! will not be included in the message"
Execution phase
i. @. E-UTRAN to UTRAN I+ mode Inter RAT &O e,ec+tion %hase. The so+rce eNode/ contin+es to recei#e do0n1in* and +%1in* +ser %1ane PDUs. Step 1. The so+rce MME com%1etes the %re%aration %hase to0ards so+rce eNode/ "! sendin the messae &ando#er Command (Taret to o+rce Trans%arent Container$ E-RA/s to Re1ease 'ist$ /earers +"4ect to Data or0ardin 'ist). The ?/earers +"4ect to Data for0ardin 1ist? IE ma! "e inc1+ded in the messae and it sha11 "e a 1ist of 5Address(es) and TEID(s) for +ser traffic data for0ardin5 recei#ed from taret side in the %re%aration %hase (Step 7 of the %re%aration %hase) 0hen 5Direct or0ardin5 a%%1ies$ or the %arameters recei#ed in te%
2hen the timer e,%ires and IR Acti#ated is not indicated "! the taret N the so+rce MME re1eases a11 "earer reso+rces of the UE. If er#in 2 chane is indicated and this timer e,%ires the so+rce MME de1etes the EP "earer reso+rces "! sendin De1ete ession Re3+est (Ca+se) messaes to the o+rce er#in 2. Ca+se indicates to the o+rce er#in 2 that the er#in 2 chanes and the o+rce er#in 2 sha11 not initiate a de1ete %roced+re to0ards the PDN 2. If er#in 2 chane is indicated and has "een acti#ated "efore this %roced+re$ the ca+se a1so indicates to the o+rce 2 that the o+rce 2 sha11 de1ete the "earer reso+rces on the other o1d CN node "! sendin De1ete /earer Re3+est messae(s) to that CN node. U%on recei%t of the or0ard Re1ocation Com%1ete Ac*no01ede messae the taret N starts a timer if the taret N a11ocated 2 reso+rces for indirect for0ardin. Step 7. The taret N 0i11 no0 com%1ete the &ando#er %roced+ re "! informin the er#in 2 (for er#in 2 re1ocation this 0i11 "e the Taret er#in 2) that the taret N is no0 res%onsi"1e for a11 the EP /earer Conte,ts the UE has esta"1ished. This is %erformed in the messae Modif! /earer Re3+est (N T+nne1 End%oint Identifier for Contro1 P1ane$ NAPI(s)$ N Address for Contro1 P1ane$ N Address(es) and TEID(s) for User Traffic for the acce%ted EP "earers (if Direct T+nne1 is not +sed) or RNC Address(es) and TEID(s) for User Traffic for the acce%ted EP "earers (if Direct T+nne1 is +sed) and RAT t!%e$ IR Acti#ated) %er PDN connection. If the PDN 2 re3+ested UE5s 1ocation and;or User C information (determined from the UE conte,t)$ the N a1so inc1+des the User 'ocation Information IE and;or User C Information IE in this messae. If the UE Time 6one has chaned$ the N inc1+des the UE Time 6one IE in this messae. If indicated$ the information IR Acti#ated indicates that IR is acti#ated$ 0hich is on1! %ossi"1e 0hen the 2 is not chaned. 2hen the Modif! /earer Re3+est does not indicate IR Acti#ated and 2 is not chaned$$ the 2 de1etes an! IR reso+rces "! sendin a De1ete /earer Re3+est to the other CN node that has "earer reso+rces on the 2 reser#ed. The N re1eases the non-acce%ted EP /earer conte,ts "! trierin the /earer Conte,t deacti#ation %roced+re. If the er#in 2 recei#es a D ' %ac*et for a non-acce%ted "earer$ the er#in 2 dro%s the D' %ac*et and does not send a Do0n1in* Data Notification to the N. Step 8. The er#in 2 (for er#in 2 re1ocation this 0i11 "e the Taret er#in 2) ma! inform the PDN 2(s) the chane of for e,am%1e for er#in 2 re1ocation or the RAT t!%e that e.. can "e +sed for charin$ "! sendin the messae Modif! /earer Re3+est %er PDN connection. The 2 a1so inc1+des User 'ocation Information IE and;or UE Time 6one IE and;or User C Information IE if the! are %resent in step 7. er#in Net0or* sho+1d "e inc1+ded if it is recei#ed in step 4. or er#in 2 re1ocation$ the er#in 2 a11ocates D' TEIDs on ;< e#en for non-acce%ted "earers. The PDN 2 m+st ac*no01ede the re3+est 0ith the messae Modif! /earer Res%onse. In the case of er#in 2 re1ocation$ the PDN 2 +%dates its conte,t fie1d and ret+rns a Modif! /earer Res%onse (Charin Id$ MIDN$ etc.) messae to the er#in 2. The MIDN is inc1+ded if the PDN 2 has it stored in its UE conte,t. If PCC infrastr+ct+re is +sed$ the PDN 2 informs the PCR a"o+t the chan e of$ for e,am%1e$ the RAT t!%e.
Step . The er#in 2 (for er#in 2 re1ocation this 0i11 "e the Taret er#in 2) ac*no01edes the +ser %1ane s0itch to the taret N #ia the messae Modif! /earer Res%onse (Ca+se$ er#in 2 T+nne1 End%oint Identifier for Contro1 P1ane$ er#in 2 Address for Contro1 P1ane$ Protoco1 Confi+ration O%tions). At this stae the +ser %1ane %ath is esta"1ished for a11 EP /earer conte,ts "et0een the UE$ taret RNC$ taret N if Direct T+nne1 is not +sed$ er#in 2 (for er#in 2 re1ocation this 0i11 "e the Taret er#in 2) and PDN 2. If the er#in 2 does not chane$ the er#in 2 sha11 send one or more ?end mar*er? %ac*ets on the o1d %ath immediate1! after s0itchin the %ath. Step 1!. 2hen the UE reconises that its c+rrent Ro+tin Area is not reistered 0ith the net0or*$ or 0hen the UE5s TIN indicates ?UTI?$ the UE initiates a Ro+tin Area U%date %roced+re 0ith the taret N informin it that the UE is 1ocated in a ne0 ro+tin area. It is RAN f+nctiona1it! to %ro#ide the PMM-CONNECTED UE 0ith Ro+tin Area information. The taret N *no0s that an IRAT &ando#er has "een %erformed for this UE as it recei#ed the "earer conte,t(s) "! hando#er messaes and therefore the taret N %erforms on1! a s+"set of the RAU %roced+re$ s%ecifica11! it e,c1+des the conte,t transfer %roced+res "et0een so+rce MME and taret N. Step 11. 2hen the timer started at ste% > e,%ires$ the so+rce MME sends a Re1ease Reso+rces messae to the o+rce eNode/. The o+rce eNode/ re1eases its reso+rces re1ated to the UE. 2hen the timer started in ste% > e,%ires and if the so+rce MME recei#ed the er#in 2 chane indication in the or0ard Re1ocation Res%onse messae$ it de1etes the EP "earer reso+rces "! sendin De1ete ession Re3+est (Ca+se) messaes to the o+rce er#in 2. Ca+se indicates to the o+rce er#in 2 that the o+rce er#in 2 sha11 not initiate a de1ete %roced+re to0ards the PDN 2. The o+rce er#in 2 ac*no01edes 0ith De1ete ession Res%onse (Ca+se) messaes. If IR has "een acti#ated "efore this %roced+re$ the ca+se a1so indicates to the o+rce 2 that the o+rce 2 sha11 de1ete the "ear er reso+rces on the other o1d CN node "! sendin De1ete /earer Re3+est messae(s) to that CN node. Step 12. If indirect for0ardin 0as +sed then the e,% ir! of the timer at so+rce MME started at step 6 triers the so+rce MME to send a De1ete Indirect Data or0ardin T+nne1 Re3+est messae to the 2 to re1ease the tem%orar! reso+rces +sed for indirect for0ardin. Step 13. If indirect for0ardin 0as +sed and the er#in 2 is re1ocated$ then the e,%ir! of the timer at taret N started at ste% > triers the taret N to send a De1ete Indirect Data or0ardin T+nne1 Re3+est messae to the taret 2 to re1ease tem%orar! reso+rces +sed for indirect for0ardin.
