TD-LTE and TD-SCDMA dual-network interoperability

[Abstract] article Xiamen Mobile for TD-LTE and TD-SCDMA dual-network interoperability testing focus to sort out the study summed up the collection and analysis tools with signaling on TD-LTE and TD-SCDMA dual-network interoperability The core network signaling message analysis methods and experience, experience in reference to the other cities.

[Keywords] TD-LTE TD-SCDMA interoperability signaling analysis 1 Introduction China Mobile 3G technology TD-SCDMA standard features of the TD-LTE evolution direction with the introduction of the TD-LTE network, network has become a multi-network collaboration network: GSM After years of construction, and network optimization, the most widely covered by the basic mobile services, carrying voice, SMS and low-speed data services, TD-SCDMA provide enhanced mobile services can carry moderate rate business and part of the voice business, TD-LTE carrying high-speed data services.

Network interoperability is the basis of the multi-network work together to ensure user awareness, balance the network load involving core network, wireless network, business hosting, terminal interoperability between TD-LTE and 2G/3G systems, including the boot in flow strategy, the idle state re-election strategy and connection-state switching strategy.

With the TD-LTE network deployment, TD-LTE and existing TD-SCDMA dual-network interoperability gradually become the focus, dual-network interoperability success is directly related to the perception of the user as well as follow-up dual-network strategy set . Xiamen Mobile for TD-LTE and TD-SCDMA dual-network interoperability core network part of the boot in the flow signaling, the idle state re-election signaling research and test validation, for interoperability testing key point to sort out, summarizes using the signaling method of collection and analysis tools to analyze the core network signaling messages TD-LTE and TD-SCDMA dual-network interoperability and experience.

2 signaling collected Xiamen Mobile TD-LTE scale technology test test < > TD-LTE and TD-SCDMA interoperability requirements to test the following items:

(1 mobile users roaming from Gn / Gp SGSN network to the MME network initiated the attachment

(2 mobile users roaming from the MME network attached to Gn / Gp SGSN network initiated

(3 mobile users in the ECM-IDLE state re-election to the UTRAN cell caused by RAU

(4 mobile users in the UTRAN PMM_IDLE state re-election to the E-UTRAN cause TAU.
All tests were requested core network signaling capture analysis (including: IuPS interface, Gr interface, Gn interface, S1 interface, S6a interface, S11 interface. Contrast signaling processes, and to check the relevant network element on the user status information.

Core network interfaces using different collection methods, specifically, as shown in Table 1:

The 3 signaling analysis analysis and comparison of the interface signaling processes each test project with expectations are the same, check the signaling messages keyword section is expected, to refining check key point. Analysis shows that each of four test items below:
3.1 mobile users roam from Gn / Gp SGSN network the MME network initiated attached to the test to verify that the dual-mode end-users roaming from the TD-SCDMA network to TD-LTE network launched attached to the Old GUTI success attachment TD -LTE network.

(The expected signaling processes expected signaling processes shown in Figure 1 (see next page.
(UE boot initiated attached to existing network signaling analysis, send Attach Request message (carrying the Old GUTI: the "MME Group ID: 55596/MME Code: 6/M-TMSI: eb025ae3, as well as the Additional GUTI: MME Group ID: 32773 / MME Code: 1/M-TMSI: e00001be ".

New MME Send Identification Request Message Response Identification Response message to the Old SGSN (carry LAC: 55596/RAC: 2/P-IMSI: eb065ae3., Old SGSN (P-TMSI Signature Mismatch is displayed, do not carry the IMSI and safety vector.

New MME sends Identity Request message (type IMSI to the UE, UE response Identity Response message (carrying IMSI.
New MME Authentication Information Request message is sent to the HSS (carrying IMSI, request an EPS safety vector, HSS Response Authentication Information Answer Message (1 set of EPS security vector.

New MME initiated authentication process (RAND / the AUTN.
New MME initiated security processes (not open security algorithms do not carry SecurityKey.
New MME Update Location Request message sent to the HSS, HSS response Update Location Answer message (carrying the MSISDN and user QoS contract.
New MME Serving GW initiated the the Create Session process, the establishment of the default bearer.
New MME sends Initial Context Setup Request to the eNode B, pass-through Attach Accept message (carrying New GUTI: the MME Group ID: 32773/MME Code: 1/M-TMSI: e00001c1 ", the message contained in the Activate Default EPS Bearer Context Request message, called for the establishment of the default bearer.

UE returns Attach Complete eNode B return to the Initial Context Setup Response message is, the establishment of the default bearer was successful.
New MME Serving GW sends the Modify Bearer Request message (update the eNode B address and TEID, Serving GW response success message.
(3 Test Summary 1Attach Request message carries the Old GUTI the Additional GUTI, which the Old GUTI contains the original TD-SCDMA network LAC / RAC / P-TMSI information.

The Old GUTI of "MME Group ID: 55596/MME Code: 6/M-TMSI: eb025ae3",

LAC = MME Group ID: 55596,


The RAC = M-TMSI,: eb025ae3 byte 5,6 = "02",


P-TMSI = "M-TMSI: eb025ae3" of RAC replaced by "06" = "eb065ae3".
GUTI and P-TMSI corresponds to the relationship shown in Figure 2 (see next page.
Attached to success, Attach Accept message carries New GUTI (MME Group ID: 32773/MME Code: 1/M-TMSI: e00001c1 the GUTI in the user registration during the MME.

Of 2New MME according to the the DNS resolver Old S

The GSN Send Identification Request message carrying the original TD-SCDMA network "LAC: 55596/RAC: 2/P-IMSI: eb065ae3" information (conversion of information described above, the purpose is to get to the Old SGSN the UE through the P-IMSI IMSI information but Old SGSN Response Identification Response message display P-TMSI Signature Mismatch, do not carry the IMSI and safety vector.

3 because New MME Old SGSN Get IMSI and safety vector failed, it launched Identity processes get IMSI directly to the UE by the MME.
4New MME to HSS for authentication parameters.
5New MME initiated authentication process (using RAND / AUTN, open security process, but is not turned on security algorithms, do not carry SecurityKey.

6HSS received Update Location Request messages sent New MME Cancel Location to the Old SGSN trigger process does not delete the user context.

(4 experience points the tests need to focus on:

Whether they carry 1Attach Request Old GUTI, the Old GUTI and P-TMSI conversion is correct, Attach Accept whether they carry the New GUTI.
2DNS analytic ability to correctly point to the Old SGSN.
3New MME Identification process to the P-TMSI to get IMSI whether to Old SGSN normal.
4 authentication parameter access and authentication process is normal.
5 security process real open security algorithms, carrying the security key.
6HSS whether to trigger the the Cancel Location process delete the user information on the Old SGSN.
7UE default bearer is successfully created.
3.2 mobile users to roam from the MME network Gn / Gp SGSN network initiated attached to the test to verify that the dual-mode end-users roaming from the TD-LTE network to TD-SCDMA network, user initiated adheres to the success of the TD-SCDMA network attached.

(The expected signaling processes expected signaling processes as shown in Figure 3:

(2 existing network signaling UE boot initiated attachment sent Attach Request messages (carry "the Old the P-TMSI: e00101c1/LAC: 32773/RAC: 1", and "Additional P-TMSI: eb065ae3/LAC of: 556/RAC: 217. "
New SGSN sends the Identification Request to the the Old MME (carrying Old P-TMSI: e00101c1/LAC: 32773/RAC: 1, Old the MME Response Identification Response message (carrying IMSI.

New SGSN through CommonID ​​under IMSI to the UE.
New SGSN to HSS launched Authentication Information flow authentication parameters (based on TD-SCDMA network is set to obtain a set of authentication parameters.

The New SGSN initiate the authentication process (using RAND / the AUTN.
The New SGSN initiated security processes (to adopt EncryptKey / IntegrityKey.
The New SGSN launched Update Location processes, HLR processes triggered Insert Subscriber Data.
The New SGSN an Attach Accept message to the UE (carry New P-TMS: ed064385I/LAC: 55596/RAC: 2.
UE returns Attach Complete message to the New SGSN.

Links to free papers Download Center http://eng.hi138.com
(3 Test Summary 1Attach Request message carrying "Old P-TMSI: e00101c1/LAC: 32773/RAC: 1", "LAC: 32773/RAC: "non-TD-SCDMA network within the RAI, the New SGSN needs initiated to DNS resolution requests to Get Old MME address.

The adhesion after successful, Attach Accept message carrying New P-TMS: ed064385I/LAC: 55596/RAC: 2 ", the P-TMSI in the user will register during the SGSN.

2New SGSN the Old MME address to send DNS resolution Identification Request message carrying the original LTE network "Old P-TMSI: e00101c1/LAC: 32773/RAC: 1" information (SGSN without the need for conversion, by Old P-IMSI Get to the Old MME of the UE IMSI information, Old MME Identification Response to the New SGSN (carry the IMSI.

3New SGSN through CommonID ​​under the IMSI to the UE.
4New SGSN to HSS for authentication parameters.
The launched authentication process 5New SGSN (normal the RAND / AUTN and security processes (open security algorithms, to adopt EncryptKey / IntegrityKey.

6New SGSN initiated Update Location flow to the HSS, HSS trigger Insert Subscriber Data flow.
7Old MME Serving GW initiated the the Delete Session process, delete the default bearer.

(4 experience points the tests need to focus on:

1Attach Request carry Old P-TMSI, Attach Accept whether they carry the New P-TMSI.
2DNS resolve the correct point to New MME.
P-TMSI 3New SGSN Identification process to the Old MME obtain IMSI whether positive.
4 authentication parameter access and authentication process is normal.
5 security process real open security algorithms, carrying the security key.
6Old MME is normal delete user information, the user information does not exist.
7Old MME Delete Session processes successfully remove the default bearer.

3.3 mobile users in the ECM-IDLE state re-election to the UTRAN cell caused by RAU

The test to verify the dual-mode end-users in the ECM-IDLE state success initiated from the TD-LTE network routing area update (RAU to TD-SCDMA network.

(1 is expected to signaling processes expected signaling processes shown in Figure 4 (see next page.
(2 existing network signaling analysis UE sends the RAU Request message to the New SGSN (carrying the "Old P-TMSI: e00101cb/LAC: 32773/RAC: 1" and "Additional P-TMSI: ed064385/LAC: 556/RAC: 217 . "
New SGSN sends SGSN Context Request message to the the Old MME (carrying "Old P-TMSI: e00101cb/LAC: 32773/RAC: 1, Old the MME returns SGSNContext Response message (IMSI to carry MM Context, PDP Context.

New SGSN through CommonID ​​under IMSI to the UE.
The New SGSN initiated security processes (carry from the Old MME MM Context the pass to EncryptKey and IntegrityKey.
The New SGSN Send SGSN Context Acknowledge message to Old MME.
The New SGSN Update PDP Context Request messages (sent to the PDN GW carry SGSN address IP of the TEID: 72001db4, QoS, RAT Type, LocationInfo.
PDN GW to the New SGSN sends Update PDP Context Response message (carrying the PDN GW address IP, the TEID: 0b0410df the QoS.
New SGSN sends Update Location Request message update location to the HSS.
HSS sends Insert Subscriber Data to New SGSN, insert the subscription data, New SGSN returns Insert Subscriber Data Acknowledge confirmation insert signed data.

HSS Response Update Location Acknowledge.
New SGSN sends the RAU Accept response UE (Family New P-TMSI,: ee064a9d/LAC: 55596/RAC: 2.
UE response RAU Complete message.
Old MME sending Delete Session Request message to the Serving GW delete bearer context, Serving GW returns Delete Session Response message, delete carrying the success.

(3 Test Summary 1RAU Request message carries the "Old P-TMSI:

e00101cb/LAC: 32773/RAC: 1 "," LAC: 32773/RAC: 1 "non-TD-SCDMA network within the RAI, the New SGSN needs initiated to DNS resolution requests Get Old MME address.

The RAU success, RAU Accept message carries the "New P-TMSI: ee064a9d /

LAC: 55596/RAC: 2 ", the P-TMSI in the user will register during the SGSN.
2New SGSN sends SGSN Context Request message to the the Old MME address DNS resolution, carry the original LTE network "Old P-TMSI: e00101cb/LAC: 32773/RAC: 1" information (SGSN without the need for translation purpose by Old P- Get the UE IMSI IMSI to the Old MME, MM is context, the PDP Context.

Old MME Reply SGSN Context Response to New SGSN (carrying IMSI, MM Context, PDP Context.
3New SGSN through CommonID ​​under the IMSI to the UE.
4New SGSN initiated security processes (to use MM Context from Old MME the pass to EncryptKey and IntegrityKey.
5New SGSN to the PDN GW initiated Update PDP Context process (notice SGSN address IP and the PDN GW address ip QoS negotiation.
6New SGSN initiated Update Location flow to the HSS, HSS trigger Insert Subscriber Data flow.
7Old MME Serving GW initiated the the Delete Session process, delete the bearer.

(4 experience points the tests need to focus on:

1RAU Request whether they carry the Old P-TMSI, RAU Accept whether they carry the New P-TMSI.
2DNS resolve the correct point to New MME.
3New SGSN SGSN Context process to the P-TMSI Old MME Get TMSI, MM Context, PDP Context is normal.
4 authentication parameters as well as the authentication process is normal configuration (according to the parameters of the existing network, TD-SCDMA.

Whether 5New SGSN use initiated from the Old MME Get EncryptKey and IntegrityKey, the security process.
Whether 6New SGSN Update PDP Context process PDN GW the GSN address IP circulars and QoS negotiation.
7Old MME is normal delete user information, the user information does not exist.
8Old MME deleted successfully carrying through Delete Session.

3.4 mobile users in UTRAN

PMM_IDLE state, re-election to the E-UTRAN, caused TAU

The test verify the dual-mode end-users in UTRAN PMM_IDLE state success initiated from the TD-SCDMA network tracking area update (TAU to TD-LTE network.

(1 expected signaling processes expected signaling flow is shown in Figure 5.
(2 existing network signaling analysis UE sends the TAU Request message to the New MME (carrying the Old GUTI: the MME Group ID: 55596/MME Code: 6/M-TMSI: ee024a9d ", and the Additional GUTI: MME Group ID: 32773 / MME Code: 1/M-TMSI: e00001cb ".

New MME sends SGSN Context Request message to the the Old SGSN (carrying the Old GUTI: MME Group ID: 55596/MME Code: 6/M-TMSI: ee064a9d "the Old SGSN Back SGSN Context Response message (carrying IMSI, MM Context, PDP Context .

New MME to HSS send Authentication Information Request (carrying the IMSI, request an EPS safety vector, HSS Response Authentication Information Answer Message (1 set of EPS security vector.

New MME initiated authentication process (RAND / the AUTN.
New MME initiated security processes (not open security algorithms do not carry SecurityKey.
New MME sends SGSN Context Acknowledge message to the Old SGSN.
New MME Serving GW sends a Create Session Request message (carrying carrying information.
Serving GW to New MME sends Create Session Response message (Bearer create success.

New MME to HSS sends Update Locat

update the location of the ion Request message (IMSI, to carry VPLMN, the RAT Type.
HSS response Update Location Answer message containing the signed data (QoS contract to carry the MSISDN and users.
New MME sends TAU Accept response UE (carry New GUTI: the "MME Group ID: 32773/MME Code: 1/M-TMSI: e00001d2.
UE response TAU Complete message.
(3 Test Summary 1TAU Request message carries the Old GUTI the Additional GUTI, which the Old GUTI contains the original TD-SCDMA network LAC / RAC / P-TMSI information.

Old GUTI "MME Group ID: 55596/MME Code: 6/M-TMSI: ee024a9d",

LAC = MME Group ID: 55596,


The RAC = M-TMSI,: the first 5,6 bytes of the ee024a9d = "02",


P-TMSI = "M-TMSI: ee024a9d" RAC is replaced by "06" = "ee064a9d".
The TAU success, TAU Accept message carries New GUTI (MME Group ID: 32773/MME Code: 1/M-TMSI: e00001d2 the GUTI in the user registration during the MME.

2New MME the Old SGSN address DNS resolution sends SGSN Context Request message carrying the original TD-SCDMA network LAC: 55596/RAC: 2/P-IMSI: ee064a9d (conversion of information described above, by P -IMSI to the Old SGSN obtain the UE IMSI, MM Context, PDP Context information.

Old SGSN Reply SGSN Context Response to New MME (carrying the IMSI, MM Context, PDP Context.
3New MME to HSS for authentication parameters.
4New MME initiated authentication process (using RAND / AUTN, open security process, but is not turned on security algorithms, do not carry SecurityKey.

5New MME Serving GW initiated the Create Session process (Bearer create successful.
6New MME to HSS initiated Update Location flow (MSISDN and IMSI obtain user QoS contract.

(4 experience points the tests need to focus on:

Whether they carry the 1TAU Request Old GUTI, the Old GUTI AND P-TMSI conversion is correct, TAU Accept whether they carry the New GUTI.

2DNS analytic ability to correctly point to the Old SGSN.
The SGSN Context process, 3New MME P-TMSI to the Old SGSN Get IMSI, MM Context, PDP Context is normal.
4 authentication parameter access and authentication process is normal.
5 security process real open security algorithms, carrying the security key.
6Old SGSN is normal delete user information, the user information does not exist.
Whether or not to initiate 7New MME Create Session process successfully created bearer.
4 Conclusions and recommendations for TD-LTE and TD-SCDMA dual-network interoperability test core network part of the boot in the stream and idle state re-election signaling analysis, summary of test results, refining the tests need to focus on the key point, to other cities to provide TD-LTE and TD-SCDMA dual-network interoperability experience, network optimization maintenance personnel can understand interoperable signaling processes and interoperability of the core network part of the principle the same time, through the existing network The signaling analysis also < > Some additions and amendments to proposals to improve the interoperability test specification.

In view of the above test results, TD-LTE and existing TD-SCDMA dual-network interoperability to meet basic needs, follow-up, mature TD-LTE terminal is recommended to carry out the the connection state switching test, and the dual network policy settings to further meet Users rich usage scenarios.

References:

[1] TD-SCDMA research and development and industrial projects Expert Group TD-LTE working group. TD-LTE scale technology test - between six cities testing -TD-LTE/3G/2G system interoperability test specification [S] 2012.

[2] 3GPP TS 23.401 Version9.11.0 Release 9 General Packet Radio Service (GPRS enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN access [S]. 2011.

[3] 3GPP TS 23.060 Version9.11.0 Release 9 General Packet Radio Service (GPRS Service description Stage 2 [S]. 2011.

[4] Jiang Yihua, Xu curtain hung learning Jiande, etc. 3GPP System Architecture Evolution (SAE principles and design [M] Beijing: People's Posts and Telecommunications Press, 2010.

Links to free papers Download Center http://eng.hi138.com

Computer Network Papers