Multiplex communications – Data flow congestion prevention or control – Control of data admission to the network
Reexamination Certificate
2000-08-21
2003-01-21
Yao, Kwang Bin (Department: 2664)
Multiplex communications
Data flow congestion prevention or control
Control of data admission to the network
C370S468000, C375S225000
Reexamination Certificate
active
06510137
ABSTRACT:
FIELD OF INVENTION
This invention relates to a method for configuring a telecommunication system comprising at least one sending entity and at least one receiving entity, said sending and receiving entities implementing a step for transmission of data transported on at least one physical channel, said at least one physical channel transmitting a transport channel composite under formation and having its own maximum physical rate, said transport channel composite comprising at least two transport channels, said data transmission step being preceded by a data processing procedure for each of said transport channels, said data processing procedure comprising at least one rate matching step, said rate matching step transforming a number of symbols before rate matching into a number of symbols after rate matching, said number of symbols after rate matching being obtained approximately by multiplying said number of symbols before rate matching by a rate matching ratio specific to each of said at least two transport channels, said transport channel composite having a number of symbols approximately equal to the algebraic sum of the numbers of symbols in the transport channels after the rate matching steps in said processing procedures for a period common to said processing procedures.
The 3GPP (3
rd
Generation Partnership Project) Committee is an organization whose members originate from various regional standardization organizations and particularly the ETSI (European Telecommunication Standardization Institute) for Europe and the ARIB (Association of Radio Industries and Businesses) for Japan, and the purpose of which is to standardize a 3
rd
generation telecommunication system for mobiles. The CDMA (Code Division Multiple Access) technology has been selected for these systems. One of the fundamental aspects distinguishing 3
rd
generation systems from 2
nd
generation systems, apart from the fact that they make more efficient use of the radio spectrum, is that they provide very flexible services. 2
nd
generation systems offer an optimized radio interface only for some services, for example the GSM (Global System for Mobiles) system is optimized for voice transmission (telephony service). 3
rd
generation systems have a radio interface adapted to all types of services and service combinations.
Therefore, one of the benefits of 3
rd
generation mobile radio systems is that they can efficiently multiplex services that do not have the same requirements in terms of Quality of Service (QoS), on the radio interface. In particular, these quality of service differences imply that the channel encoding and channel interleaving should be different for each of the corresponding transport channels used, and that the bit error rates (BER) are different for each transport channel. The bit error rate for a given channel encoding is sufficiently small when the Eb/I ratio, which depends on the coding, is sufficiently high for all coded bits. Eb/I is the ratio between the average energy of each coded bit (Eb) and the average energy of the interference (I), and depends on the encoding. The term symbol is used to denote an information element that can be equal to a finite number of values within an alphabet, for example a symbol may be equivalent to a bit when it can only be one of two values.
The result is that since the various services do not have the same quality of service, they do not have the same requirement in terms of the Eb/I ratio. But yet, in a CDMA type system, the capacity of the system is limited by the level of interference. Thus, an increase in the energy of bits coded for a user (Eb) contributes to increasing interference (I) for other users. Therefore, the Eb/I ratio has to be fixed as accurately as possible for each service in order to limit interference produced by this service. An operation to balance the Eb/I ratio between the different services is then necessary. If this operation is not carried out, the Eb/I ratio would be fixed by the service with the highest requirement, and the result will be that the quality of the other services would be “too good”, which would have a direct impact on the system capacity in terms of the number of users. This causes a problem, since rate matching ratios are defined identically at both ends of the radio link.
This invention relates to a method for configuring a telecommunication system to define rate matching ratios identically at both ends of a CDMA type radio link.
In the ISO's (International Standardization Organization) OSI (Open System Interconnection) model, a telecommunication equipment is modeled by a layered model comprising a stack of protocols in which each layer is a protocol that provides a service to the higher level layer. The 3GPP committee calls the service provided by the level 1 layer to the level 2 layer “transport channels”. A transport channel (TrCH for short) enables the higher level layer to transmit data with a given quality of service. The quality of service is characterized in particular by a processing delay, a bit error rate and an error rate per block. A transport channel may be understood as a data flow at the interface between the level 1 layer and the level 2 layer in the same telecommunication equipment. A transport channel may also be understood as a data flow between the two level 2 layers in a mobile station and in a telecommunication network entity connected to each other through a radio link. Thus, the level 1 layer uses suitable channel encoding and channel interleaving, in order to satisfy the quality of service requirement.
Solutions proposed by the 3GPP committee to achieve this balancing are illustrated in
FIGS. 1 and 2
.
FIG. 1
is a diagrammatic view illustrating multiplexing of transport channels on the downlink according to the current proposal of the 3GPP committee. In the current proposal of this committee, the symbols processed until the last step
130
described below are bits.
With reference to
FIG. 1
, a higher level layer
101
periodically supplies transport block sets to the level 1 layer. These sets are supplied in transport channels reference
100
. A periodic time interval with which the transport block set is supplied to the transport channel is called the Transmission Time Interval (TTI) of the transport channel. Each transport channel has its own TTI time interval which may be equal to 10, 20, 40 or 80 ms.
FIG. 2
shows examples of transport channels A, B, C and D. In this figure, the transport block set received by each transport channel is represented by a bar in the histogram. The length of the bar in the histogram represents a TTI interval of the associated transport channel and its area corresponds to the useful load in the transport block set. With reference to
FIG. 2
, the duration of the TTI intervals associated with transport channels A, B, C and D is equal to 80 ms, 40 ms, 20 ms and 10 ms respectively. Furthermore, the dotted horizontal lines in the histogram bars indicate the number of transport blocks in each transport block set. In
FIG. 2
, transport channel A receives a first transport block set A
0
comprising three transport blocks during a first transmission time interval, and a second transport block set A
1
comprising a single transport block during the next TTI interval. Similarly, transport channel B receives transport block sets B
0
, B
1
, B
2
and B
3
during four consecutive TTI intervals, comprising 0, 2, 1 and 3 transport blocks respectively. Transport channel C receives transport block sets C
0
to C
7
during eight successive TTI intervals and finally transport channel D receives transport block sets D
0
to D
15
during sixteen TTI intervals.
Note that a TTI interval for a given transport channel cannot overlap two TTI intervals in another transport channel. This is possible because TTI intervals increase geometrically (10 ms, 20 ms, 40 ms and 80 ms). Note also that two transport channels with the same quality of service necessarily have the same TTI intervals. Furthermore, the term “transport format” is used to describe the informat
Mitsubishi Electric Telecom Europe (S.A.)
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Yao Kwang Bin
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