Abstract:
The present invention concerns a method, a device, a mobile terminal and a base station for transferring data from a mobile terminal to a base station after a wireless resource enabling the transfer of the data from the mobile terminal to the base station has been allocated. The method comprises the steps, executed by the mobile terminal, of transferring, information indicating whether or not an allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station, the information indicating that no allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station being transferred by setting the power of pilot symbols to a null value, receiving, from the base station, allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed, and transferring the data to the base station in the wireless resource indicated as allocated to the mobile terminal.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to telecommunication systems and in particular, to a method and a device for transferring signals representative of a pilot symbol pattern to a telecommunication device. 
     2. Description of the Related Art 
     In some telecommunication networks, the access by the mobile terminals to the resources of the telecommunication medium is decided by the base station. 
     In uplink scheduling scheme, when a mobile terminal needs to transfer data through the base station, the mobile terminal sends a message to the base station requesting a pilot symbol pattern to be allocated. The base station allocates to each mobile terminal a pilot symbol pattern, for a pilot allocation time duration which is as example of 20 milliseconds. During the pilot allocation time duration, each second telecommunication device  20  transfers periodically, as example every millisecond and at the same time to the base station, signals representative of the pilot symbol pattern it has been allocated. 
     The base station determines the channel conditions which exist between itself and each mobile terminal using the signals received which are representative of the pilot symbol patterns. The base station selects the mobile terminal which has to transfer data to the base station according to the determined channel conditions. 
     In such technique, when a mobile terminal needs to transfer data to the base station, it must transfer periodically as example every millisecond, during all the pilot allocation time duration, signals representative of the pilot symbol pattern to the base station. 
     If the channel conditions which exist between that mobile terminal and the base station are better than the ones which exist between the other mobile terminals and the base station, the base station selects that mobile terminal as the one which has to transfer data to the base station. However, the selected terminal may have no more data to transfer to the base station. In such case, the resources of the telecommunication system are used inefficiently. 
     Furthermore, if the mobile terminal has no more data to transfer, it must use the electric power resources in order to transfer periodically signals representative of the pilot symbol pattern to the base station. Such case is not satisfactory also in term of electric power consumption. 
     One solution could be to reduce the pilot allocation time duration in order to avoid that problem but such solution increases a lot the messages exchanged between the mobile terminals and the base station and then, the resources of the telecommunication system are still used inefficiently. 
     It has to be noted also that, in the prior art, the pilot symbol patterns are transferred for the only purpose of the channel conditions determination. 
     SUMMARY OF THE INVENTION 
     The aim of the invention is therefore to propose methods and devices which allow an improvement of the above mentioned technique and which enable to use signals representative of a pilot symbol pattern for another purpose than channel conditions determination, in order to improve the use of the resources of the telecommunication system and to better use of the electric power resources. 
     To that end, the present invention concerns a method for transferring data from a mobile terminal to a base station after a wireless resource enabling the transfer of the data from the mobile terminal to the base station has been allocated, the mobile terminal performing the method comprising: 
     transferring, information indicating whether or not an allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station, the information indicating that no allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station being transferred by setting the power of pilot symbols to a null value. 
     receiving, from the base station, allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed, and 
     transferring the data to the base station in the wireless resource indicated as allocated to the mobile terminal. 
     According to a particular feature, the information indicating whether or not the allocated wireless resource is needed for the transfer of data from the mobile terminal to the base station is needed is transferred periodically. 
     According to a particular feature, a pilot symbol allocated to the mobile terminal is orthogonal to another pilot symbol allocated to another mobile terminal. 
     According to a particular feature, the data is transferred as packets. 
     The present invention concerns a method of transferring data from a mobile terminal to a base station after a wireless resource enabling the transfer of the data from the mobile terminal to the base station has been allocated, the base station performing the method comprising; 
     receiving, from the mobile terminal, information indicating whether or not an allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station, the information indicating that no allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station being transferred by setting the power of piloy symbols to a null value 
     transferring, to the mobile terminal, allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed, and 
     receiving, from the mobile terminal, the data in the wireless resource indicated as allocated to the mobile terminal. 
     According to a particular feature, the information indicating whether or not the allocated wireless resource is needed for the transfer of data from the mobile terminal to the base station is received periodically. 
     According to a particular feature, the base station allocates othogonal pilot symbols to at least two mobile terminals. 
     According to a particular feature, the data is received as packets. 
     The present invention concerns also a device for transferring data from a mobile terminal to a base station after a wireless resource enabling the transfer of the data from the mobile terminal to the base station has been allocated, wherein the device for transferring of the data is included in the mobile terminal and comprises: 
     means for transferring, to the base station, information indicating whether or not an allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station, the information indicating that no allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station being transferred by setting the power of pilot symbols to a null value; 
     means for receiving, from the base station, allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed; and 
     means for transferring data to the base station in the wireless resource indicated as allocated to the mobile terminal. 
     The present invention concerns a device for transferring data from a mobile terminal to a base station after a wireless resource enabling the transfer of the data from the mobile terminal to the base station has been allocated, wherein the device for transferring of the data is included in the base station and comprises; 
     means for receiving, from the mobile terminal, information indicating whether or not an allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station, the information indicating that no allocated wireless resource is needed for the tranfer of the data from the mobile terminal to the base station being transferred by setting the power of pilot symbols to a null value; 
     means for transferring, to the mobile terminal, allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed, and 
     means for receiving, from the mobile terminal, the data in the wireless resource indicated as allocated to the mobile terminal. 
     The present invention concerns a mobile terminal that transfers data to a base station after a wireless resource enabling the transfer of the data from the mobile terminal to the base station has been allocated, the mobile terminal comprising: 
     an interface that transmits, to the base station, information indicating whether or not an allocated, wireless resource is needed for the transfer of the data from the mobile terminal to the base station, the information indicating that no allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station being transferred by setting the power of pilot symbols to a null value, wherein the interface receives, from the base station. Allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed; and 
     a processing unit that transfers the data to the base station in the wireless resource indicated as allocated to the mobile terminal. 
     The present invention concerns a base station that receives data from a mobile terminal after a wireless resource enabling the reception of the data from the mobile terminal has been allocated, the base station comprising: 
     an interface that receives, from the mobile terminal, information indicating whether or not an allocated wireless resource is needed for the reception of the data from the mobile terminal, the information indicating that no allocated wireless resource is needed for the transfer of the data from the mobile terminal to the base station being transferred by setting the power of pilot symbols to a null value; and 
     a processing unit that transfers, to the mobile terminal, allocation information indicating that the wireless resource is allocated to the mobile terminal when the information indicates that the allocated wireless resource is needed, wherein 
     the interface receives the data from the mobile terminal in the wireless resource indicated as allocated to the mobile terminal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The characteristics of the invention will emerge more clearly from a reading of the following description of an example embodiment, the said description being produced with reference to the accompanying drawings, among which: 
         FIG. 1  is a diagram representing the architecture of the wireless network according to the present invention; 
         FIG. 2  is a diagram representing the architecture of a first telecommunication device according to the present invention; 
         FIG. 3  is a diagram representing the architecture of a second telecommunication device according to the present invention; 
         FIG. 4  is an example of representing of signals transferred in a uplink channel 
         FIG. 5  is an algorithm executed by each second telecommunication device according to the present invention; 
         FIG. 6  is an algorithm executed by the first telecommunication device according to the present invention; 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a diagram representing the architecture of the wireless network according to present invention. 
     In the telecommunication system of the  FIG. 1 , at least one and preferably plural second telecommunication devices  20   1  or  20   K  are linked through a network  15  to a first telecommunication device  10  through an uplink and a downlink channel. 
     The network is as example and in a non limitative a wireless network  15  but the present invention is also applicable to wired networks like power line networks. 
     Preferably, and in a non limitative way, the first telecommunication device  10  is a base station or a node or an enhanced node of the wireless network  15  or terminals like mobile phones, personal digital assistants, or personal computers. 
     Preferably, and in a non limitative way, the second telecommunication devices  20   1  to  20   K  are terminals like mobile phones, personal digital assistants, or personal computers. 
     As example, the telecommunication network  15  is a wireless telecommunication system which uses Time Division Duplexing scheme (TDD) or Frequency Division Duplexing scheme (FDD). 
     In TDD scheme, the signals transferred in uplink and downlink channels are duplexed in different time frames in the same frequency band. The signals transferred within the wireless network  15  share the same frequency spectrum. 
     In FDD scheme, the signals transferred in uplink and downlink channels are duplexed in different frequency bands. 
     When the first telecommunication device  10  transfers data, signals or messages to a second telecommunication device  20 , the data, signals or messages are transferred through the downlink channel. 
     When a second telecommunication device  20  transfers signals or data to the first telecommunication device  10 , the signals or data are transferred through an uplink time slot of the uplink channel. Preferably, the data are transferred under the form of at least one packet. 
     The first telecommunication device  10  receives from the second telecommunication devices  20  messages requesting a pilot symbol pattern to be used in the uplink channel. The first telecommunication device  10  allocates to each second telecommunication device  20 , for a pilot allocation time duration, a pilot symbol pattern. Each allocated pilot symbol pattern is orthogonal from the other allocated pilot symbol patterns. During the pilot allocation time duration, each second telecommunication device  20  transfers the pilot symbol pattern it has been allocated through the uplink channel. 
     The first telecommunication device  10  determines the channel conditions which exist between itself and each second telecommunication device  20  using the signals received which are representative of the pilot symbol patterns. The first telecommunication device  10  allocates next uplink time frame to one of the second telecommunication device  20  for which channel conditions is considered as good i.e. the received power of the signal is upper than a predetermined value. 
     According to the invention, at least one second telecommunication device  20  sets the transmission power of the signals representative of a pilot symbol pattern according to the data it has to transfer. 
     The first telecommunication device  10  comprises at least one antenna noted BSAnt and each second telecommunication device comprises  20   1  to  20   K  at least one antenna noted respectively MS 1 Ant to MSKAnt. 
       FIG. 2  is a diagram representing the architecture of a first telecommunication device according to the present invention. 
     The first telecommunication device  10  has, for example, an architecture based on components connected together by a bus  201  and a processor  200  controlled by the program related to the algorithm as disclosed in the  FIG. 6 . 
     It has to be noted here that the first telecommunication device  10  is, in a variant, implemented under the form of one or several dedicated integrated circuits which execute the same operations as the one executed by the processor  200  as disclosed hereinafter. 
     The bus  201  links the processor  200  to a read only memory ROM  202 , a random access memory RAM  203  and a channel interface  205 . 
     The read only memory ROM  202  contains instructions of the programs related to the algorithm as disclosed in the  FIG. 6  which are transferred, when the first telecommunication device  10  is powered on to the random access memory RAM  203 . 
     The RAM memory  203  contains registers intended to receive variables, and the instructions of the programs related to the algorithm as disclosed in the  FIG. 6 . 
     The channel interface  205  enables the transfer of information representative of pilot symbol patterns which are allocated to each second telecommunication device  20 . An information representative of a pilot symbol pattern is the pilot symbol pattern or an information, like an indicia, identifying the pilot symbol pattern. 
     Through the channel interface  205 , the processor  200  indicates in a downlink time frame, which second telecommunication device  20  has to transfer a packet in the next uplink time frame. 
     The channel interface  205  comprises means for analysing the signals representative of pilot symbol patterns transferred by each second telecommunication device  20  in order to determine the channel conditions of each second telecommunication device  20 , i.e., the channel conditions between the first telecommunication device  10  and each second telecommunication device  20 . 
       FIG. 3  is a diagram representing the architecture of a second telecommunication device according to the present invention. 
     The second telecommunication device  20 , as example the second telecommunication device  20   k  with k comprised between 1 and K, has, for example, an architecture based on components connected together by a bus  301  and a processor  300  controlled by programs related to the algorithm as disclosed in the  FIG. 5 . 
     It has to be noted here that the second telecommunication device  20   k  is, in a variant, implemented under the form of one or several dedicated integrated circuits which execute the same operations as the one executed by the processor  300  as disclosed hereinafter. 
     The bus  301  links the processor  300  to a read only memory ROM  302 , a random access memory RAM  303  and a channel interface  305 . 
     The read only memory ROM  302  contains instructions of the program related to the algorithm as disclosed in the  FIG. 5  which are transferred, when the first telecommunication device  20   k  is powered on to the random access memory RAM  303 . 
     The RAM memory  303  contains registers intended to receive variables, and the instructions of the program related to the algorithm as disclosed in the  FIG. 5 . 
     The RAM memory  303  memorizes into a transmission queue, the data which are under the form of packets to be transferred by the second telecommunication device  20  to the first telecommunication device  10 . 
     The channel interface  305  comprises means for transferring packets and signals representative of a pilot symbol pattern to the first telecommunication device  10 . The channel interface  305  comprises means for controlling the power  310  of the signals representative of a pilot symbol pattern. As example and in a non limitative way, the means for controlling the power  310  of the signals representative of a pilot symbol pattern multiply the signals representative of a pilot symbol by a coefficient noted P determined by the processor  300 . 
     The channel interface  305  comprises means for receiving in the downlink time frames, the pilot symbol pattern which is allocated to the second telecommunication device  20  and indication authorizing the second telecommunication device  20  to transfer packet in the next uplink time frame. 
       FIG. 4  is an example of representing of signals transferred in the uplink channel. 
     The  FIG. 4  shows two pilot allocation time durations noted PST 1  and PST 2 . Each pilot allocation time duration PST 1  or PST 2  is around 20 milliseconds. 
     Each pilot allocation time duration PST 1  or PST 2  is decomposed into N time frames noted FR 1 , FR 2  to FRN. 
     Each time frame FR 1 , FR 2  to FRN is decomposed into a time slot noted respectively PS 1 , PS 2  to PSN and a time slot noted respectively PCK 1 , PCK 2  to PCKN. 
     During the pilot allocation time duration PST 1 , each second telecommunication device  20  transfers in the time slots noted PS 1 , PS 2  to PSN signals representatives of the pilot symbol pattern the first telecommunication device  10  has allocated to the second telecommunication device  20 . The transmission power of the signals representatives of the pilot symbol pattern is adjusted according to information associated to data to be transferred. 
     It has to be noted here that, if the transmission power of the signals representatives of the pilot symbol pattern is set to null value for a time slot PSn with 1≦n≦N, the transmission of the signals representatives of the pilot symbol pattern can be also understood as a non transmission of the signals in the time slot PSn. 
     During the pilot allocation time duration PST 2 , each second telecommunication device  20  transfers in the time slots noted PS 1 , PS 2  to PSN, signals representatives of the pilot symbol pattern the first telecommunication device has allocated to the second telecommunication device  20 . The transmission power of the signals representatives of the pilot symbol pattern is adjusted according to information associated to data to be transferred. 
     The pilot symbol pattern allocated to a second telecommunication device  20  in the pilot allocation time duration PST 1  is equal to or different from the pilot symbol pattern allocated to the second telecommunication device  20  in the pilot allocation time duration PST 2 . 
     In each time slot PCK 1 , PCK 2  to PCK 3 , a second telecommunication device  20  transfers packet to the first telecommunication device if the first telecommunication device  10  has allocated that time slot to the second telecommunication device  20 . 
       FIG. 5  is an algorithm executed by each second telecommunication device according to the present invention. 
     The second telecommunication device  20 , more precisely the processor  300 , executes the present algorithm. 
     At step S 500 , the processor  300  commands the transfer through the uplink channel of a message requesting to the first telecommunication device  10  the allocation of a pilot symbol pattern to be used by the second telecommunication device  20  in the uplink channel. 
     At next step S 501 , the processor  300  memorizes in the RAM memory  303 , the pilot symbol pattern allocated by the first telecommunication device  10  using information representative of the pilot symbol pattern received through the downlink channel. 
     At the same time, the processor  300  determines the pilot allocation time duration PST 1 . The pilot allocation time duration PST 1  is determined by reading a predetermined field in the message comprising the allocated pilot symbol pattern or is determined by reading a predetermined value memorized in the ROM memory  302 . 
     At next step S 502 , the processor  300  checks if there is a packet in the transmission queue to be transferred to the first telecommunication device  10 . 
     If there is a packet in the transmission queue, the processor  300  moves to step S 503 , otherwise the processor  300  moves to step S 506 . 
     At step S 503 , the processor  300  checks if the quality of service which is associated to the first packet comprised in the transmission queue is high. As example and in a non limitative way, a packet to which a high quality of service is associated is a packet which needs to be transferred within a time limit like a packet comprising a data related to a telephone call or a video content. A packet to which a low quality of service is associated is, as example, a packet which comprises a text content for which the transmission delay is not essential. 
     If the quality of service which is associated to the first packet comprised in the transmission queue is high, the processor  300  moves to step S 504 . 
     If the quality of service which is associated to the first packet comprised in the transmission queue is low, the processor  300  moves to step S 505 . 
     At step S 504 , the processor  300  sets the value of the coefficient P to P 1  and transfers it to the channel interface  305  which controls the power of the signals representative of a pilot symbol pattern by multiplying the signals representative of a pilot symbol pattern by the value P 1  of the coefficient P. After that, the processor  300  moves to step S 507 . 
     At step S 505 , the processor  300  sets the value of the coefficient P to P 2 , with P 2 &lt;P 1  and transfers it to the channel interface  305  which controls the power of the signals representative of a pilot symbol pattern by multiplying the signals representative of a pilot symbol pattern by the value P 2  of the coefficient P. After that, the processor  300  moves to step S 507 . 
     At step S 507 , the processor  300  transfers the pilot symbol pattern stored in the RAM memory  303  to the channel interface  305 . 
     Signals representative of the pilot symbol pattern are multiplied by the coefficient P and transferred through the uplink channel to the first telecommunication device  10 . 
     At next step S 508 , the processor  300  checks if a message is received from the first telecommunication device  10  through the downlink channel authorizing the second telecommunication device  20  to transfer a packet through in the next time frame of the uplink channel. 
     If a message authorizing the second telecommunication device  20  to transfer a packet through in the next time frame of the uplink channel is received, the processor  300  moves to step S 509 . 
     If no message authorizing the second telecommunication device  20  to transfer a packet through in the next time frame of the uplink channel is received, the processor  300  moves to step S 510 . 
     At step S 509 , the processor  300  commands the transfer of the first packet of the transmission queue to the channel interface  305 . That packet is discarded from the transmission queue. It has to be noted here that, in a preferred mode of realisation, the packet is discarded from the transmission queue only if the processor  300  detects the reception, in response to the transferred packet, of an acknowledgment message transferred by the first telecommunication device  10 . 
     At step S 510 , the processor  300  checks if the pilot allocation time duration PST ends. 
     If the pilot allocation time duration PST is not ended, the processor  300  returns to step S 502 . 
     If the pilot allocation time duration PST is ended, the processor  300  moves to step S 511 . 
     At step S 502 , the processor  300  checks if there is a packet in the transmission queue to be transferred to the first telecommunication device  10 . 
     If there is no packet in the transmission queue, the processor  300  moves to step S 506 , otherwise the processor  300  moves to step S 503 . 
     At step S 506 , the processor  300  sets the value of the coefficient P to null value, and transfers it to the channel interface  305  which controls the power of the signals representative of a pilot symbol pattern by multiplying the signals representative of the pilot symbol pattern by the null value. After that, the processor  300  moves to step S 507 . 
     The processor  300  executes the steps S 502  to S 510  as far as the pilot allocation time duration PST ends. 
     At step S 511 , the processor  300  checks whether or not, information representative of a pilot symbol pattern is received from the first telecommunication device  10  through the downlink channel for the next pilot allocation time duration. 
     If a pilot symbol pattern is received from the first telecommunication device  10 , the processor  300  returns to step S 501 . 
     If no pilot symbol pattern is received from the first telecommunication device  10 , the processor  300  moves to step S 512  and checks if there is a packet in the transmission queue to be transferred to the first telecommunication device  10 . 
     If there is a packet in the transmission queue, the processor  300  returns to step S 500 , otherwise the processor  300  stops the present algorithm. When a packet will be in the transmission queue, the processor  300  will execute again the present algorithm. 
     It has to be noted here that, in a variant of realisation, the step S 511  is not executed by the processor  300 . In such variant, the processor  300  moves from step S 510  to S 512 . 
       FIG. 6  is an algorithm executed by the first telecommunication device according to the present invention. 
     More precisely, the present algorithm is executed by the processor  200  of the first telecommunication device  10 . 
     At step S 600 , the processor  200  detects the reception through the uplink channel of messages requesting the first telecommunication device  10  the allocation of a pilot symbol pattern. The processor  200  identifies each of the second telecommunication devices which sent a message requesting the first telecommunication device  10  the allocation of a pilot symbol pattern. 
     Such messages are transferred by the second telecommunication devices  20  which need to transfer packets through the uplink channel. 
     At next step S 601 , the processor  200  allocates a pilot symbol pattern to each of the identified second telecommunication devices  20 . A pilot symbol pattern is a sequence of bits, each pilot symbol pattern is orthogonal from the other pilot symbol patterns. Information representative of each allocated pilot symbol pattern is transferred respectively to each identified second telecommunication device  20 . 
     At the same step, the processor  200  activates the pilot allocation time duration. The pilot allocation time duration PST is transferred with the pilot symbol patterns or not. The pilot allocation time duration PST is equal to a predetermined value memorized in the ROM memory  202 . 
     At next step S 602 , the processor  200  detects, through the channel interface  205 , the reception of signals representative of the pilot symbol patterns transferred by the identified second telecommunication devices  20 . 
     At next step S 603 , the processor  200  gets, from the channel interface  205 , the channel conditions which exist between itself and each second telecommunication device  20  using the signals received which are representative of the pilot symbol patterns. As example, the channel interface  205  measures, for each pilot symbol pattern, the power of the corresponding received signals. 
     At next step S 604 , the processor  200  selects, using the channel conditions, the second telecommunication device  20  to which next uplink time frame is allocated. 
     As example, the processor  200  selects the second telecommunication device  20  which transferred the signals which have the highest measured power. 
     It has to be noted here that, if each second telecommunication device  20  sets the transmission power of the signals representative of a pilot symbol pattern according to the packet it has to transfer, the probability that the first telecommunication device  10  allocates the next time frame to a second telecommunication device  20  which has a packet which has an associated high quality of service is increased. 
     Furthermore, as each second telecommunication device  20  sets the transmission power of the signals representative of a pilot symbol pattern to null value when no packets need to be transferred, the first telecommunication device  10  never allocates the next time frame to a second telecommunication device  20  which has no packet to transfer, optimizing then the resources of the wireless network  15 . 
     At next step S 605 , the processor  200  checks, for each allocated pilot symbol pattern, if signals representative of said pilot symbol pattern have not been received. 
     Such case occurs when at least one second telecommunication device  20  sets the transmission power of the signals representative of a pilot symbol pattern to null value. 
     At next step S 606 , the processor  200  sets K variables M(k), with k=1 to K to the value one or null according to the results of the step S 605 . 
     If signals representative of the pilot symbol pattern allocated to the second telecommunication device  20   k  have been received, the processor  200  sets the variable M(k) to the value one. 
     If signals representative of the pilot symbol pattern allocated to the second telecommunication device  20   k  have not been received, the processor  200  sets the variable M(k) to the null value. Thanks to that, the processor  200  is able to determine the second telecommunication devices which have no more packets to transfer at the end of the pilot allocation time duration PST. 
     At next step S 607 , the processor  200  checks if the pilot allocation time duration PST ends. 
     If the pilot allocation time duration PST is not ended, the processor  200  returns to step S 602 . 
     If the pilot allocation time duration PST is ended, the processor  200  moves to step S 608 . 
     At step S 608 , the processor  200  identifies each second telecommunication device  20  of which the variable M(k) is equal to the value one. 
     It has to be noted here that in a variant, the processor  200  counts the number of time x 1  to x K  signals representative of the pilot symbol pattern allocated respectively to the second telecommunication devices  20   1  to  20   K  have been received within the pilot allocation time duration PST. The processor  200  forms a list of pilot symbol patterns which have x k  upper than a predetermined threshold and identifies the corresponding second telecommunication devices  20 . 
     The processor  200  returns then to step S 600  of the present algorithm. 
     Naturally, many modifications can be made to the embodiments of the invention described above without departing from the scope of the present invention.