Analysis of EV-DO technology evolution and development
1 Introduction
According to the latest data released by CDG, the number of CDMA users worldwide has reached 490 million, and operators such as Veriozon, Sprint, KDDI, China Telecom, LG Telecom, Telus Mobility, and Skytel have deployed 70 commercial HRPD Rev.A commercial networks. 38 networks are under deployment, with HRPD users reaching 120 million. With the development of multimedia data services, various new business forms are constantly emerging, and users' requirements for system bandwidth are constantly increasing. In order to pursue higher service peak rates and compete with HSPA, some CDMA operators (such as KDDI, (China Telecom) has formulated an upgrade plan to HRPD Rev.B, and some operators intend to directly switch from HRPD Rev.A to LTE.
2 HRPD technology evolution
2.1 Standard evolution route
HRPD belongs to the technology of the 3GPP2 standard camp, and its standard evolution route is shown in Figure 1:
Figure 1. HRPD standard evolution route
In the roadmap, HRPD evolved from version 0 along the routes of Rev A, Rev B, and Rev C:
The forward and reverse peak rates supported by Rev 0 are 2.4Mbps and 153.6kbps, respectively. This version is proposed to provide high-speed data services, mainly for Best Effort services, especially developed for asymmetric high-speed download services.
The forward and reverse peak rates supported by Rev A are 3.1Mbps and 1.8Mbps respectively. This version enhances the QoS control mechanism and reduces the delay (low transmission delay, low switching delay), supports VoIP, and video phone ( VT), PTC and other real-time, low-latency services.
The Rev B standard was released in March 2006. This version uses multi-carrier technology, and the front and reverse peak rates can reach 73.5Mbps and 27Mbps (bundle 15 carriers). The characteristics of EV-DO Rev B are multi-carrier bundling, introducing higher-order modulation (64QAM) and larger packet length (6144bits, 7168bits, 8192bits) in the forward direction, and the forward peak rate of a single carrier can reach 4.9Mbps, The reverse peak rate of the single carrier remains unchanged at 1.8Mbps. The adoption of RevB technology can improve the user's service rate (carrier number × single carrier peak rate), which is beneficial to the improvement of user experience. There are two ways to evolve EV-DO REV A to RevB:
1) Evolution based on CSM6800
The original Rev.A system does not require hardware upgrade, only the software upgrade of BTS and BSC. This upgrade method does not support 64QAM high-order modulation and DTX / DRX. The forward peak rate of a single carrier is the same as DO RevA, which is 3.072Mbps.
2) Evolution based on CSM6850
The original RevA system needs to replace the BTS channel board with the CSM6850 chip channel board, and upgrade the software of BTS and BSC. This upgrade method supports 64QAM high-order modulation and larger packet length (6144bits, 7168bits, 8192bits), the forward peak rate of a single carrier is 4.9Mbps, the chip supports DTX / TRX, allowing the terminal to turn off the PA when there is no data to send , Tx / Rx link, can extend battery life.
The Rev C standard, the 3GPP2 standards organization began the formulation of related standards in March 2009, using OFDM, MIMO, Closed-Loop MTD and other technologies, supporting the downlink peak rate of 18.74Mbps / 1.25MHz and the reverse peak rate of 4.3Mbps /1.25MHz, planned to be released in February 2010.
UMB standard, 3GPP2 has carried out the formulation of relevant standards, and officially released the UMB air interface standard C.S0084 -0 v1.0 in the second quarter of 2007, because another 3GPP standard LTE equivalent to UMB has obtained most operations With regard to the support of vendors, the major CDMA operators tend to evolve to LTE on the issue of whether to evolve to UMB or LTE. At the end of last year, the 3GPP2 standards organization officially abandoned the UMB standard.
In another standard camp-3GPP, the standard technology equivalent to HRPD has evolved along the routes of HSDPA (R5), HSUPA (R6), HSPA + (R7, R8, R9), of which the second stage of HSPA + standard (R8 standard ) Has been distributed, and the third stage of the standard is under development (R9 standard). The main technical indicators of HRPD and HSPA are compared as follows:
Table 1. Comparative analysis of the main indicators of HRPD and HSPA
2.2 HRPD network evolution and development
Although the development of the HRPD standard started from Rel0 and experienced the evolution of Rev A, RevB, and RevC, but since HRPD Rev.A is an enhancement of HRPD Rel0, operators who began to deploy HRPD networks after 2006 will all cross HRPD Rel .0 Direct deployment of HRPD Rev.A network, HRPD Rev.B mainly uses multi-carrier bundling technology on the basis of HRPD Rev.A to further increase the peak rate. In the choice of whether to upgrade to Rev.B network, each operator will have With different options, some operators do not consider upgrading to HRPD Rev.B, and plan to directly switch from HRPD Rev.A network to LTE. Major CDMA operators have not considered evolution to HRPD Rev.C. Therefore, the evolution of the HRPD network will be as shown in Figure 2:
Figure 2. HRPD network evolution route
In the process of HRPD to LTE evolution, 1xRTT / HRPD network and LTE network will coexist for a certain period of time. Because LTE needs a long time to support voice services, and early LTE is only deployed in hotspot areas, 1xRTT is expected / The coexistence period of HRPD network and LTE will be relatively long. Therefore, interoperability between HRPD-LTE will be a key issue for CDMA network operators to consider during their evolution to LTE.
3 HRPD-LTE interoperability
3.1 Standard situation
When formulating LTE standards, the 3GPP standards organization considered interconnection with other non-3GPP systems (including CDMA systems) and required EPS (LTE wireless network E-UTRAN + core network EPC collectively referred to as EPS) to support a variety of different access systems. Provide multi-access network environment. The interoperability standards formulated by 3GPP mainly include TS22.278, TS23.402, TS23.216, TS23.276, TS23.272, TS23.203, TS29.213, TS29.214, TS29.273, TS29.275, TS29. 276, TS29.277, TS36.331, TS36.413, etc., R8 version of the main standard has been frozen in March this year.
In order to support the interconnection and interoperability with 3GPP E-UTRAN, the 3GPP2 standards organization has also launched a series of interoperable standards development work, enhancing HRPD to eHRPD, Evolved High Rate Packet Data. At present, the interoperability 1.0 version standard based on HRPD Rev.A has been released, mainly including:
Ÿ Interoperability requirements specification S.R0129-0 v1.0 released in January 2008
Ÿ Air interface specification C.S0087 -0 v1.0 released in May 2009
Ÿ IOS Specification AS 0022-0 v1.0 released in March 2009
Ÿ The core network specification X.S0057-0 v1.0 released in April 2009
According to the network conditions of various operators, in addition to the interoperability scenarios of eHRPD system based on HRPD Rev.A and LTE network, there are also interoperability scenarios of HRPD Rev.B and LTE. KDDI first proposed support based on HRPD Rev.B's eHRPD system and LTE interoperability standards development requirements, the 3GPP2 standards organization has carried out corresponding standards work, the interoperability specification S.R0129-A v1.0 was released in April 2009, and other standards are planned for the end of 2009 release.
3.2 Interoperable network architecture
The interoperability architecture (non-roaming) of 3GPP E-UTRAN and 3GPP2 eHRPD is shown in Figure 3. The eHRPD access network is interconnected with the 3GPP EPC core network through the HSGW, and the E-UTRAN-eHRPD is implemented through the S101 and S103 interfaces. Operation (If optimized handover is not required between eHRPD and E-UTRAN, S101 and S103 interfaces are not required). The interface and network element standards above the dotted line in the figure are all formulated by 3GPP, and the network element and interface standards below the dotted line are formulated by 3GPP2. The main network element and interface functions are as follows:
Figure 3. E-UTRAN-eHRPD interoperable network architecture
Ÿ eNodeB: LTE system wireless network (E-UTRAN) network element, mainly with wireless resource management, IP header compression and user data encryption, MME selection, user plane data routing to S-GW, paging and broadcast message scheduling and sending , Measurement and measurement report configuration, UE Bearer level uplink and downlink rate control, admission control and other functions.
Ÿ MME: Mobility Management EnTIty, the core network (EPC) network element of the LTE system, mainly has NAS signaling, saves and manages the UE context, UE access authentication, idle UE tracking and reachability management, S-GW and P-GW selection, HRPD node selection, HRPD signaling message transparent transmission, status information transfer between E-UTRAN and HRPD access and other functions.
Ÿ S-GW: Serving Gateway, the core network (EPC) network element of the LTE system, mainly with packet routing and forwarding, as a local mobility anchor when switching between eNodeBs, the label of the upstream and downstream data packets of the transport layer, and the upstream and downstream bearers Functions such as binding, PMIPv6 MAG (Mobile Access Gateway), DHCPv4 (relay) and DHCPv6 (relay).
Ÿ P-GW: Packet Data Network Gateway, the core network (EPC) network element of the LTE system, which mainly has data routing and forwarding, IP anchors for heterogeneous network switching, UE IP address allocation, and uplink and downlink data packets for the transport layer. Label, upstream and downstream bearer binding, PMIPv6 LMA, DSMIPv6 Home Agent, MIPV4 Home Agent and other functions.
Ÿ HSGW: HRPD Serving Gateway, with cross-eAN handover mobility management anchor, packet routing, forwarding, delivery, upstream and downstream billing, reporting to PCRF events, binding of upstream and downstream bearers based on policy information, network-based mobility Management, PMIPv6 MAG, IPv4 and IPv6 address allocation, user access authentication and authorization and other functions.
Ÿ eAN / ePCF: the wireless network node of the eHRPD system, supports interoperability with E-URRAN, compatible with HRPD and eHRPD modes, and adds the GKE (Generic Key Exchange) function between eAT and HSGW on the basis of traditional AN functions, eHRPD -Idle state switching between HRPD, idle state switching between eHRPD-E-UTRAN, active state switching and other functions.
The main interfaces related to interoperation are S101 and S103:
Ÿ S101 interface: It is the signaling interface between MME and eAN / ePCF, and supports the following signaling:
² UE transmits eHRPD air interface signaling via E-UTRAN
² UE transmits E-UTRAN air interface signaling via eHRPD
² Establishment of S103 Data forward tunnel during handover
² Switching signaling between EUTRAN and eHRPD
Ÿ S103 interface: It is the bearer interface between S-GW and HSGW, realizes the function of Data Forwarding tunnel between S-GW and HSGW, and supports GRE encapsulation. When the UE switches from the E-UTRAN to the eHRPD system, the forwarded data is sent from the S-GW to the HSGW through the tunnel.
4 Conclusion
Since the first HRPD Rel. 0 network was commercialized in 2002, the CDMA commercial network has developed to the mature HRPD Rev. A stage, and the related HRPD standard technology has been developed to the Rev. C stage (standards are being formulated), but mainstream CDMA Operators are not interested in Rev. C, but focus on the evolution of HRPD to LTE. On the issue of evolution to LTE, the interoperability of HRPD-LTE is the focus of attention of operators. Verizon, the largest mobile operator in North America, plans to start the live network test of eHRPD and LTE network interconnection in October this year. If the test results are satisfactory It will be possible to accelerate the evolution of HRPD network to LTE.
What is Feeder on the placement machine? What is Feida on the placement machine? Feida is the main accessory of the placement machine. Its function is to mount the SMD patch components on the feeder, and the feeder provides components for the placement machine for patching.
In the placement machine, the feeder functions to supply the chip component SMC/SMD to the placement head in a regular pattern and order for accurate and convenient pickup, which occupies a large number and position in the placement machine. It is also an important part of choosing a placement machine and arranging the placement process. Depending on the SMC/SMD package, feeders typically have a variety of tapes, sticks, waffles, and bulk materials.
Tape feeders with the different size such as 8mm, 16mm, 24mm, 32mm, 44mm, 56mm etc.Panasonic Feeder,Insertion Machine Tape Feeder Unit,Tape Feeder Unit,Feeder Panasonic
Shenzhen Keith Electronic Equipment Co., Ltd. , https://www.aismtks.com