Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
2000-03-09
2004-01-27
Vincent, David (Department: 2732)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S431000
Reexamination Certificate
active
06683860
ABSTRACT:
The invention relates generally to a method and an arrangement for transferring information in a packet radio service. The invention further concerns the technology of allocating resources for individual radio connections at the interface between a transmitting device and a receiving device, especially the allocation of radio resources for a packet-switched radio connection.
The term “mobile telecommunications system” refers generally to any telecommunications system which enables a wireless communication connection between a mobile station (MS) and the fixed parts of the system when the user of the mobile station is moving within the service area of the system. A typical mobile communications system is a Public Land Mobile Network (PLMN). The majority of mobile telecommunications systems in use at the time of the filing of this patent application belong to the second generation of such systems, a well-known example being the GSM system (Global System for Mobile telecommunications). However, the invention also applies to the next or third generation of mobile telecommunications systems, such as a system known as the UMTS (Universal Mobile Telecommunications System) which currently undergoes standardisation.
Multi-user radio communication systems must have well-defined procedures for allocating radio resources (time, frequency) to individual radio connections. In this patent application we will consider especially packet-switched radio connections in cellular radio systems where each cell comprises a base station which is arranged to communicate with a multitude of mobile stations. As an example we will discuss the well-known GPRS system (General Packet Radio Service), the known resource allocation procedures of which are laid down in the technical specification number GSM 04.60 published by ETSI (European Telecommunications Standards Institute) [1].
Packet switched wireless networks, such as GPRS (General Packet Radio Service), are designed to provide data services, e.g. Internet services, cost-effectively. In GPRS the channels are not dedicated to one user continuously but are shared between multiple users. This facilitates efficient data multiplexing. However, different kind of data services have different requirements for the data connection. For example, Internet real time services have gained popularity during the past few years; IP (Internet Protocol) telephony and different streaming applications are already common in the Internet. These services have different requirements for the data connection compared to, for example, transferring facsimiles or email messages. Therefore the connection for the data transfer is usually established according to the service requirements, such as the Quality of Service (QoS) requirement. This, however, makes the use of many kinds of services during the same connection difficult or impossible.
In order to better understand the problems of the prior art solutions and the idea of the present invention, the structure of a prior art digital cellular radio system is next described in short, and GPRS is then described in more detail by briefly describing some parts of said specification [1].
FIG. 1
a
shows a version of a prior known GSM cellular radio system. The terminals MS are connected to the radio access network RAN which includes the base stations and the base station controllers/radio network controllers RNC. The core network CN of a cellular radio system comprises mobile services switching centres (MSC) and related transmission systems. If the system supports GPRS services, the core network also comprises Serving GPRS Support Nodes (SGSN) and Gateway GPRS Support nodes (GGSN). According e.g. to the GSM+ specifications developed from GSM the core network may provide new services such as GPRS. The new types of radio access networks can co-operate with different types of fixed core networks CN and especially with the GPRS network of the GSM system.
FIG. 1
b
shows an architecture of a general packet radio service (GPRS). The GPRS is a new service that is currently based on the GSM system but it is supposed to be generic in the future. GPRS is one of the objects of the standardisation work of the GSM phase 2+ and the UMTS at the ETSI (European Telecommunications Standards Institute). The GPRS operational environment comprises one or more subnetwork service areas, which are interconnected by a GPRS backbone network. A subnetwork comprises a number of packet data service nodes (SN), which in this application will be referred to as serving GPRS support nodes (SGSN)
153
, each of which is connected to the mobile telecommunications system (typically to a base station through an interworking unit) in such a way that it can provide a packet service for mobile data terminals
151
via several base stations
152
, i.e. cells. The intermediate mobile communication network provides packet-switched data transmission between a support node and mobile data terminals
151
. Different subnetworks are in turn connected to an external data network, e.g. to a Public Data Network (PDN)
155
, via GPRS gateway support nodes GGSN
154
. The GPRS service thus allows the provision of packet data transmission between mobile data terminals and external data networks when the appropriate parts of a mobile telecommunications system function as an access network.
In order to access the GPRS services, a mobile station shall first make its presence known to the network by performing a GPRS attachment. This operation establishes a logical link between the mobile station and the SGSN, and makes the mobile station available for SMS (Short Message Services)
158
,
159
, over GPRS, paging via SGSN, and notification of incoming GPRS data. More particularly, when the mobile station attaches to the GPRS network, i.e. in a GPRS attachment procedure, the SGSN creates a mobility management context (MM context). Also the authentication of the user is carried out by the SGSN in the GPRS attachment procedure. In order to send and receive GPRS data, the MS shall activate the packet data address wanted to be used, by requesting a PDP activation procedure (Packet Data Protocol). This operation makes the mobile station known in the corresponding GGSN, and interworking with external data networks can commence. More particularly, a PDP context is created in the mobile station and the GGSN and the SGSN. The packet data protocol context defines different data transmission parameters, such as the PDP type (e.g. X.25 or IP), the PDP address (e.g. X.121 address), the quality of service (QoS) and the NSAPI (Network Service Access Point Identifier). The MS activates the PDP context with a specific message, Activate PDP Context Request, in which it gives information on the TLLI, the PDP type, the PDP address, the required QoS and the NSAPI, and optionally the access point name (APN).
FIG. 1
b
also shows the following GSM functional blocks: Mobile Switching Center (MSC)/Visitor Location Register (VLR)
160
, Home Location Register (HLR)
157
and Equipment Identity Register (EIR)
161
. The GPRS system is usually also connected to other Public Land Mobile Networks (PLMN)
156
.
Functions applying digital data transmission protocols are usually described as a stack according to the OSI (Open Systems Interface) model, where the tasks of the various layers of the stack, as well as data transmission between the layers, are exactly defined. In the GSM system phase 2+, which in this patent application is observed as an example of a digital wireless data transmission system, there are five operational layers defined.
Relations between the protocol layers are illustrated in FIG.
2
. The lowest protocol layer between the mobile station MS and the base station subsystem is layer
1
(L
1
)
200
,
201
, which corresponds to a physical radio connection. Above it, there is located an entity corresponding to the layers
2
and
3
of a regular OSI model, wherein the lowest layer is a radio link control/media access control (RLC/MAC) layer
202
,
203
; on top of it a log
Forssell Mika
Parantainen Janne
Nokia Mobile Phones Ltd.
Perman & Green LLP
Vincent David
LandOfFree
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