Femtocell

A, overview

Femtocell is in recent years according to the development and 3G mobile broadband tendency launched super miniaturization mobile base station. Femtoforum is actively promoting the productization organization, membership includes alcatel lucent, now AT&T, British telecom, cisco, Ericsson, huawei, zte, MOTOROLA, NEC, samsung, vodafone etc operators and equipment manufacturers.

Femtocell USES the IP protocol, with users of existing ADSL broadband connections, LAN, etc, far from driven by special gateway YiDongWang IP network to realize the unicom. Its size and ADSL modems similar, with convenient installation, automatic configuration, automatic nets gauge, plug and play features. Femtocell have suitable for CDMA, GSM and UMTS, etc. Various kinds of standards and support 2gb, 2.5 G, 3G products, and operators of other mobile base station with frequency band with formats, mobile terminal, so ok and general. It has a carrier, transmit power for 10 ~ 100 HaoWa (with WiFi, covering the AP almost) radius of 50 ~ 200 meters, support 4 ~ 6 activities users, maximum allowable velocity of 10 kilometers user/hour.

Second, Femtocell microcells type base station

Cellular base station (type Femtocel) is the use of microcells realize microcells district covers mobile communication system, it can achieve little scope namely microcells village inside the purpose of providing high-density traffic.

Microcells type base station system application purpose is to solve some signal covered the blind spot of area and the area, such as the tunnel and underground garage, underground walkways, underground shopping mall, tall buildings and top etc area; lower Second can also solve commercial center, roads, entertainment center, a convention center telephone hot spots, can reduce the signal coverage of the area's recent and improve communication quality communication; Finally, microcells type indoor distribution system deployed in high-rise buildings are also often the layer, can effectively avoid the frequent switching even phone drop words.

Third, Femtocel network structure

Femtocell is a small, low power 3G wireless equipment, it is possible to consider user phones emit voice and data transmission to a standard interface called based on the 3G core network, and it family access points can plug and play, can be connected to any existing based on IP network of teleportation, provide family range of mobile communications services.

1, Femtocell equipment

Femtocell system in nets yuan functional configuration and traditional macro cellular network have very big different, its environmental positioning is a family or small and medium-sized enterprise use, the characteristics of indoor communication different from outdoor environment of capacity demand, small and no user suddenly increase of the situation, do not need too much consider breathing effect, switch, etc. Femtocell equipment numerous, generally USES the network structure of partial flat, namely Femtocell equipment integrated traditional macro cellular network among many nets yuan functions, like NodeB, RNC SGSN, GGSN etc.; The function of Femtocell equipment for composition and device interface, manufacturers have different realization, usually function integration schemes have two kinds, the first kind is integrated NodeB, RNC function, the second is integrated with the RNC, SGSN NodeB, GGSN function.

2, Femtocell network structure

The introduction of the Femtocell equipment in principle wrong mobile core nets produce any influence, the integration of the equipment, the network structure function of the Femtocell flating, when NodeB, the RNC device integrates with the SGSN GGSN function, when the user through Femtocell equipment can directly access Internet network, beardless through mobile packet domain core nets. Femtocell equipment function with access to the core network integration is corresponding the way. This paper summarizes the Femtocell forward in recent years as the various access way, basically can be divided into three kinds.

(1) Iu - boverIP way

NodeB Femtocell equipment have only partial functions, is the first proposed Femtocell access plan, this scheme need the initial investment is small, with a macro honeycomb Femtocell can share RNC equipment, network structure is clear. Its defect is due to poor economic performance, the RNC has capacity and port restrictions, ideally by large capacity macro cellular base station occupy port, the Femtocell exactly is port consumption low capacity allocation equipment, number are numerous and online at the same time, killing RNC equipment user rarely with capacity of the waste. Port The RNC core nets and Femtocell equipment as ordinary NodeB to handle, the network structure and the traditional 3G nets are the same. This mode can implement sex differences.

(2) RAN gateway way

NodeB Femtocell equipment integrated the RNC's part function, and the latest Femtocell access scheme is put forward in the core nets and IP access into a new nets yuan between that RAN a gateway. RAN IuOverIP interface collected from the gateway to the Femtocell business, then through standard Iu - CS, Iu - PS port distributed to the core nets. RANGateWay (RGW) way to initial investment is small, little effect on core network. Core network will RGW as ordinary RNC equipment processing, RGW responsible for network security, business gathering, protocol conversion, Femtocell equipment management and configuration and the Femtocell equipment of access control.

(3) SIP/IMS way

NodeB Femtocell equipment integrated the RNC functions, is with the Femtocell and core network based on SIP agreement between the connection mode, operators and based on the construction of a core nets, SIP protocol with existing grouping, data core network synchronization operation, by the new core network Femtocell users provide services. Its defect is need will macro cellular network existing business copied to SIP Internet, plus the construction of new core network fee, the initial investment is larger.

SIP/IMS way is the ultimate goal of network development, but in core network upgrades to IMS whole IP network, this way before investment is bigger, maintenance costs is high. Operators may be more inclined to choose with a smooth RGW equipment of upgrading.

Because have business transparency, low cost, small advantages of network effect, currently most manufacturers chose RGW implementation. In reality, each manufacturer provides emtocell equipment is often integrated WiFi, ADSL family gateway functions such as comprehensive product, some also provides Gi interface, which makes mobile users can access the Internet through a Femtocell equipment directly, without the need for access network mobile packet domain core nets.