Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2001-05-15
2004-12-07
Vo, Nguyen T. (Department: 2686)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S525000, C455S560000, C370S331000
Reexamination Certificate
active
06829482
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention pertains to telecommunications, and particularly to the switching from dedicated to common channels in a wireless telecommunications system.
2. Related Art and other Considerations
In a typical cellular radio system, mobile user equipment units (UEs) communicate via a radio access network (RAN) to one or more core networks. The user equipment units (UEs) can be mobile stations such as mobile telephones (“cellular” telephones) and laptops with mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-included, or car-mounted mobile devices which communicate voice and/or data with radio access network.
The radio access network (RAN) covers a geographical area which is divided into cell areas, with each cell area being served by a base station. A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each cell is identified by a unique identity, which is broadcast in the cell. The base stations communicate over the air interface (e.g., radio frequencies) with the user equipment units (UE) within range of the base stations. In the radio access network, several base stations are typically connected (e.g., by landlines or microwave) to a radio network controller (RNC). The radio network controller, also sometimes termed a base station controller (BSC), supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
One example of a radio access network is the Universal Mobile Telecommunications (UMTS) Terrestrial Radio Access Network (UTRAN). The UTRAN is a third generation system which is in some respects builds upon the radio access technology known as Global System for Mobile communications (GSM) developed in Europe. UTRAN is essentially a wideband code division multiple access (W-CDMA) system.
As those skilled in the art appreciate, in W-CDMA technology a common frequency band allows simultaneous communication between a user equipment unit (UE) and plural base stations. Signals occupying the common frequency band are discriminated at the receiving station through spread spectrum CDMA waveform properties based on the use of a high speed, pseudo-noise (PN) code. These high speed PN codes are used to modulate signals transmitted from the base stations and the user equipment units (UEs). Transmitter stations using different PN codes (or a PN code offset in time) produce signals that can be separately demodulated at a receiving station. The high speed PN modulation also allows the receiving station to advantageously generate a received signal from a single transmitting station by combining several distinct propagation paths of the transmitted signal. In CDMA, therefore, a user equipment unit (UE) need not switch frequency when handoff of a connection is made from one cell to another. As a result, a destination cell can support a connection to a user equipment unit (UE) at the same time the origination cell continues to service the connection. Since the user equipment unit (UE) is always communicating through at least one cell during handover, there is no disruption to the call. Hence, the term “soft handover.” In contrast to hard handover, soft handover is a “make-before-break” switching operation.
The Universal Mobile Telecommunications (UMTS) Terrestrial Radio Access Network (UTRAN) accommodates both circuit switched and packet switched connections. In this regard, in UTRAN the circuit switched connections involve a radio network controller (RNC) communicating with a mobile switching center (MSC), which in turn is connected to a connection-oriented, external core network, which may be (for example) the Public Switched Telephone Network (PSTN) and/or the Integrated Services Digital Network (ISDN). On the other hand, in UTRAN the packet switched connections involve the radio network controller communicating with a Serving GPRS Support Node (SGSN) which in turn is connected through a backbone network and a Gateway GPRS support node (GGSN) to packet-switched networks (e.g., the Internet, X.25 external networks)
There are several interfaces of interest in the UTRAN. The interface between the radio network controllers (RNCs) and the core network(s) is termed the “Iu” interface. The interface between a radio network controller (RNC) and its base stations (BSs) is termed the “Iub” interface. The interface between the user equipment unit (UE) and the base stations is known as the “air interface” or the “radio interface” or the “Uu interface”. In some instances, a connection involves both a Serving or Source RNC (SRNC) and a target or drift RNC (DRNC), with the SRNC controlling the connection but with one or more diversity legs of the connection being handling by the DRNC (see, in this regard, U.S. patent application Ser. No. 09/035,821 filed Mar. 6, 1998, entitled “Telecommunications Inter-Exchange Measurement Transfer”; and U.S. patent application Ser. No. 09/035,788 filed Mar. 6, 1998, entitled “Telecommunications Inter-Exchange Congestion Control”, both of which are incorporated herein by reference). The interface between a SRNC and a DRNC is termed the “Iur” interface.
The Universal Mobile Telecommunications (UMTS) has both common transport channels and dedicated transport channels. The common transport channels are the random access channel (RACH), the forward access channel (FACH), the common packet channel (CPCH), and the downlink shared channel (DSCH). The dedicated transport channels include the dedicated channel (DCH). These transport channels are described, e.g., in one or more of the following three specifications:
(1) 3GPP TS 25.211, v.3.2.0 “Physical Channels and Mapping of Transport Channels Onto Physical Channels (FDD)”.
(2) 3GPP TS 25.221, v.3.2.0 “Physical Channels and Mapping of Transport Channels Onto Physical Channels (TDD)”.
(3) 3GPP TS 25.331, v.3.2.0 “RRC Protocol Specification”.
In the foregoing, “3GPP” refers to a project known as the Third Generation Partnership Project (3GPP), which has undertaken to evolve further the UTRAN and GSM-based radio access network technologies.
From a resource management point of view, the downlink shared channel (DSCH) is managed by the network (UTRAN) in a similar way as the dedicated channel (DCH). Thus, from the resource management point of view, the downlink shared channel (DSCH) is essentially a dedicated resource. Accordingly, as used herein, a “common channel” is any one of the common transport channels excluding the downlink shared channel (DSCH), and a “dedicated channel” herein means dedicated transport channels and the downlink shared channel (DSCH).
On various occasions, it may be necessary or desirable to switch from a common channel to a dedicated, or conversely from a dedicated channel to a common channel, using what has been termed “channel switching”. Various techniques for channel switching are described in the following United States Patent Applications, all of which are incorporated herein by reference: U.S. patent application Ser. No. 09/429,497 (attorney reference 2380-150), filed Oct. 28, 1999, entitled “Channel-Type Switching To A Common Channel Based On Common Channel Load”; U.S. patent application Ser. No. 09/457,141 (attorney reference 2380-165), filed Dec. 8, 1999, entitled “Channel-Type Switching Control”; U.S. patent application Ser. No. 09/537,689, filed Mar. 29, 2000, entitled “Channel-Type Switching Based On Cell Load”.
When switching a connection from common channels to dedicated channels in UMTS, the network (UTRAN) selects the radio resources. Furthermore, in order to request that the user equipment unit (UE) switch to the selected dedicated channels, the network (UTRAN) sends information describing the selected resources to the user equipment unit (UE) using certain signaling messages in a physical channel reconfiguration procedure, as described, e.g., in 3GPP TS 25.331, v.3.2.0 “RRC Protocol Specification”. In the context of this pa
Rune Göran
Van Lieshout Gert-Jan
Fox Bryan
Nixon & Vanderhye P.C.
Telefonaktiebolaget LM Ericsson (publ)
Vo Nguyen T.
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