3G Wireless Networks

The Home Agent (HA) is the third major component to the CDMA2000 packet data service network and should be compliant with IS-835, which is relevant to the HA functionality within a wireless network. The HA performs many tasks, some of ... [full story]

The AAA server is another new component associated with CDMA2000 deployment. The AAA provides, as its names implies, authentication, authorization, and accounting functions for the packet data network associated with CDMA2000 and utilizes the Remote Access Dial-In User Service (RADIUS) ... [full story]

The PDSN is a new component associated with a CDMA2000 system, as compared to cdmaOne networks. The PDSN is an essential element in the treatment of packet data services that will be offered, and its location in the CDMA2000 network ... [full story]

CDMA2000, whether 1X or 3X, requires upgrades to the radio and network architecture of the existing system. It is important to note that the migration path for a CDMA2000 operator will be from 1X to 3X if the CDMA2000 platform ... [full story]

CDMA2000 is a unique radio and network access system that is part of the IMT-2000 specification suite of access platforms that comprise what is known collectively as third generation (3G). The International Mobile Telecommunications 2000 (IMT-2000) specification from the International ... [full story]

Figure 6-29 shows the network architecture for a new core network domain planned for 3GPP Release 5. This architecture has already been described in Chapter 4, “Third Generation (3G) Overview.” It is important to note that this architecture represents an ... [full story]

3GPP Release 4 introduces a significant enhancement to the core network architecture as it applies to the CS domain. Basically, the MSC is broken into constituent parts and it is allowed to be deployed in a distributed manner, as shown ... [full story]

The core network architecture for 3GPP Release 1999 is not greatly different than the core network architecture of GSM/GPRS. Clearly, the core network must be upgraded to support the new interfaces to the radio access network, but a completely new ... [full story]

UMTS supports two main categories of handovers—soft handovers and hard handovers.A soft handover is make-before-break, whereby communication exists between the UE and more than one cell for a period of time.A hard handover is break-before-make, whereby communication with the first ... [full story]

From a network perspective, packet data services in the 3GPP Release 1999 architecture use largely the same mechanisms as used for GPRS data, the big difference being the user data rates that can be supported. One notable difference is that ... [full story]

The procedure for the establishment of a basic speech call in UMTS is shown in Figure 6-23 (NBAP messaging has been omitted). The process begins with an access request from the UE. This access request is sent either on the ... [full story]

The interface between RNCs is the Iur interface. The primary purpose of this interface is to support inter-RNC mobility (SRNS relocation) and a soft handover between Node Bs connected to different RNCs. The protocol architecture for the Iur interface is ... [full story]

The protocol architecture for the Iub interface is shown in Figure 6-21. This is the interface between an RNC and the Node B that it controls. In the protocol architecture, we again find the transport network control plane as was ... [full story]

The protocol architecture for the Iu-PS interface is shown in Figure 6-20.We first notice that no transport network control protocol is involved. It is not needed because of the protocol that is used in the user plane. Specifically, in the ... [full story]

If we apply this generic structure to the Iu-CS interface (RNC to MSC), then it appears as shown in Figure 6-19. The application protocol in the control plane is the Radio Access Network Application Part (RANAP). This provides functionality similar ... [full story]

Figure 6-18 provides a generic model for the terrestrial interfaces used in UTRAN—the Iu-CS, Iu-PS, Iur, and Iub interfaces. Each interface has two main components—the radio network layer and the transport network layer. The radio network layer represents the application ... [full story]

The RNC that controls a given Node B is known as the Controlling RNC (CRNC). The CRNC is responsible for the management of radio resources available at a Node B that it supports. For a given connection between the UE ... [full story]

In most mobile communications networks, the network architecture can be split into two main parts—the access network and the core network. The access network is specific to the access technology being used, whereas the core network is shielded from the ... [full story]

 Figure 6-15 shows the structure of the downlink DPDCH and DPCCH. The most notable characteristic is that the DPCCH is time-multiplexed with the DPDCH rather than being transmitted separately. In each slot on the downlink, two fields contain DPDCH user ... [full story]

 Figure 6-14 shows the structure of the uplink DPCCH as used with the uplink DPDCH. The DPCCH is transmitted in parallel with the DPDCH and the information in a given DPCCH frame relates to the corresponding DPDCH frame. The ... [full story]

WCDMA is designed to offer great flexibility in the transmission of user data across the air interface. For example, data rates can change on a frame-by-frame basis (every 10 ms). Moreover, it is possible to mix and match different types ... [full story]

In any CDMA system, power control is of critical importance. Because all users share the same frequency at the same time, it is important that one user not transmit at such a high power that other users are drowned ... [full story]

As shown in Figure 6-8, information is passed from the MAC layer to the physical layer in the form of transport channels. That information, however, can begin higher in the protocol stack, in which case it is passed from the ... [full story]

The process for accessing the uplink begins with the transmission from the terminal of a specific preamble sent on a specific access slot. This preamble is 4,096 chips long and comprises 256 repetitions of a 16-chip signature. The preamble is ... [full story]

 As mentioned, information from upper layers is passed to the physical layer through a number of transport channels. These transport channels are mapped to a number of physical channels on the air interface. In general, a physical channel is identified ... [full story]

 In general, two types of transport channels exist. These are common transport channels and dedicated transport channels. Common transport channels may be applicable either to all users in a cell or to one or more specific users. In the case ... [full story]

At the physical layer, the UE and the network communicate via a number of physical channels. Many of these physical channels are used to carry information that is passed to the physical layer from higher layers. Specifically, information is passed ... [full story]

We have already mentioned some of the types of physical channels defined in WCDMA. In fact, many different channel types exist, and the various types of channels are defined in a logical hierarchy. Figure 6-8 shows the overall logical structure ... [full story]

As is the case for the uplink, the downlink uses QPSK modulation. The process in the downlink is the same as that shown in Figure 6-5 for the uplink. Each complex-valued chip is split into its constituent real and imaginary ... [full story]

The downlink scrambling codes are used to separate the transmissions of one cell from those of another. The downlink scrambling codes are Gold codes similar to the long scrambling codes used in the uplink. As is the case for the ... [full story]

With the exception of the synchronization channels (SCHs), the downlink channels are spread to the chip rate and scrambled, as shown in Figure 6-6. Each channel to be spread is split into two streams—the I branch and the Q branch. ... [full story]

As is the case for the uplink, a number of channels are used in the downlink. In fact, more channels are defined for the downlink than for the uplink. That is because the downlink includes pilot channels, synchronization channels, channels ... [full story]