Multiplex communications – Diagnostic testing – Determination of communication parameters
Reexamination Certificate
2001-08-16
2003-04-08
Nguyen, Steven (Department: 2665)
Multiplex communications
Diagnostic testing
Determination of communication parameters
C370S335000, C370S342000, C719S323000
Reexamination Certificate
active
06545983
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for configuring a telecommunication system comprising at least one sending entity and at least one receiving entity implementing a phase of communicating data conveyed by several transport channels distributed into at least two groups of transport channels, said transport channels of one and the same group requiring to be received with one and the same ratio Eb/I of the average energy of a bit to the average energy of the interference, said phase of communication of the sending entity comprising processing procedures specific to the groups of transport channels, each processing procedure comprising a rate matching step, said rate matching step ensuring the transformation of an input block of an initial size into an output block of a final size as a function of a given rate matching ratio, a maximum puncture rate being defined for each processing procedure.
2. Discussion of the Background Art
The 3GPP (3
rd
Generation Partnership Project) group is an association whose members originate from several regional standardization bodies including in particular the ETSI (European Telecommunication Standardization Institute) and the ARIB (Association of Radio Industries and Businesses). Its object is the standardization of a third-generation telecommunication system for mobiles. One of the fundamental aspects distinguishing third-generation from second-generation systems is that, apart from the fact that they will use the radio spectrum more efficiently, they will allow very great flexibility of service. Second-generation systems offer an optimized radio interface for certain services. For example GSM (Global System for Mobiles) is optimized for the transmission of speech (telephony). Third-generation systems will offer a radio interface adapted for all kinds of services and combinations of services.
One of the issues at stake with third-generation mobile radio systems is that of efficiently multiplexing, on the radio interface, services which do not have the same demands in terms of quality of service (QoS). Quality of service is defined, conventionally, according to at least one criterion comprising in particular a processing delay, a bit error rate and/or an error rate per transported block. These different qualities of service require corresponding transport channels having different channel codings and channel interleavings. Moreover, they demand different maximum bit error rates (BER). For a given channel coding, the demand with regard to the BER is satisfied when the coded bits have at least a certain coding-dependent ratio Eb/I. The ratio Eb/I expresses the ratio of the average energy of each coded bit to the average energy of the interference.
It follows that the different qualities of service do not have the same demand in terms of the ratio Eb/I. Now, in a system of the CDMA (Code Division Multiple Access) type, the capacity of the system is limited by the level of interference. It is therefore necessary to fix the ratio Eb/I as correctly as possible for each service. Therefore, a rate matching operation, for balancing the ratio Eb/I is necessary between the various services. Without this operation the ratio Eb/I would be fixed by the service having the greatest demand, and as a result the other services would have “too good” a quality, thereby impacting directly on the capacity of the system.
This raises a problem since it is necessary in some manner that the rate matching ratios be defined identically at the two ends of the radio link.
The present invention relates to a configuring method for defining rate matching ratios identically at the two ends of a CDMA radio link.
In the OSI model (Open System Interconnection) from the ISO (International Standardization Organization), a telecommunication equipment is modelled by a layered model constituting a stack of protocols where each level is a protocol supplying a service to the level above. Level
1
is in particular responsible for implementing channel coding and channel interleaving. The service supplied by level
1
is referred to as “transport channels”. A transport channel allows the higher level to transmit data with a certain quality of service. The quality of service is in particular characterized by the delay and the BER.
In order to satisfy the quality of service demand, level
1
uses a certain encoding and a suitable channel interleaving.
The known solutions, and in particular those proposed in the 3GPP project, will be described with regard to the first few drawings in which:
Represented in
FIGS. 1 and 2
are the block diagrams for interleaving and multiplexing as defined by the current proposal by the 3GPP group, although this proposal has not yet been finalized.
In these figures, similar blocks bear the same numbers. In both cases the uplink (from the mobile station to the network) may be distinguished from the downlink (from the network to the mobile station), and only the transmission part is represented.
Each transport channel, labelled
100
, periodically receives a transport blocks set from an higher level, labelled
102
. The number of transport blocks
100
in this set, as well as their sizes, depend on the transport channel. The minimum period at which the transport blocks set is supplied corresponds to the time span of the interleaving of the transport channel. The transport channels with one and the same quality of service (QoS) are processed by one and the same processing chain
103
A,
103
B.
In each of the processing chains
103
A,
103
B, the transport channels, in particular after channel encoding and channel interleaving, are multiplexed together by concatenation in step
104
. This multiplexing is carried out per multiplexing frame. A multiplexing frame is the smallest unit of data for which demultiplexing may be carried out at least partially. A multiplexing frame typically corresponds to a radio frame. The radio frames form consecutive time intervals synchronized with the network, and numbered by the network. In the proposal by the 3GPP group, a radio frame corresponds to a duration of 10 ms.
The 3GPP proposal comprises the service-specific coding and interleaving option represented diagrammatically at
103
C. The possibility of such an option is being considered at present since its indispensability or otherwise has not yet been determined.
In the general case, a processing chain
100
A firstly comprises a step
106
during which a bit word termed the FCS (Frame Check Sequence) is attached to each transport block. The bit word FCS is typically calculated by the so-called CRC technique (Cyclic Redundancy Check) which consists in considering the bits of the transport block to be the coefficients of a polynomial P and in calculating the CRC from the remainder of the polynomial (P+P
0
) after dividing by a so-called generating polynomial G, where P
0
is a predefined polynomial for a given degree of P. The attachment of the bit word FCS is optional, and certain transport channels do not include this step. The exact technique for calculating the bit word FCS also depends on the transport channel, and especially on the maximum size of the transport blocks. The usefulness of the bit word FCS is in detecting whether the transport block received is valid or corrupted.
The next step
108
consists in multiplexing together the transport channels (TrCH) of like quality of service (QoS). This is because those transport channels which have the same quality of service may use the same channel coding. Typically, the multiplexing at
108
is carried out by concatenating the transport blocks sets with their FCS for each transport channel.
The next step, labelled
110
, consists in performing the channel encoding.
On exit from the channel encoder
110
there is a set of coded blocks. Typically, in the case of a convolutional code, we have either zero or a single coded block of variable length. The length is given by the formula:
N
output
=N
input
/(coding rate)+
N
tail
(length of the coded block).
Mitsubishi Electric Telecom Europe
Nguyen Steven
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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