Multiplex communications – Communication over free space – Combining or distributing information via time channels
Reexamination Certificate
1999-10-01
2003-06-03
Maung, Nay (Department: 2681)
Multiplex communications
Communication over free space
Combining or distributing information via time channels
C370S341000, C370S337000, C370S442000, C370S468000
Reexamination Certificate
active
06574212
ABSTRACT:
The present invention relates to devices for transmitting and receiving data in a digital telecommunication system, as e. g. a base station or a mobile terminal, and to a method for transmitting and receiving random access bursts in a random access channel of a digital telecommunication system.
In a telecommunication system, data are communicated between base stations and mobile stations. Thereby, the communication area is divided in cells, in which one base station communicates with one or more mobile stations. The data transmission from a mobile station to a base station is called uplink and the data transmission from a base station to one or more mobile stations is called downlink. For the uplink and the downlink, several transmission channels for the transmission of control and user data are available, e. g. a broadcast control channel, a synchronization channel, a user data channel, a random access channel etc. In some telecommunication systems, a communication also between mobile terminals is possible.
A communication device of the telecommunication system, as e. g. a base station or a mobile terminal, may not have an existing dedicated connection to another communication device of the telecommunication system, but may wish to start the transmission of control or user data. An example of such data may be an initial setup message to be sent from a mobile terminal to a base station to establish a first signaling connection. Usually, the random access channel is used for this purpose since it does not require prior negotiation, whereby the random access channel is accessed randomly by the communication device (usually a mobile terminal) requiring a connection. Thereby, the random access data transmitted from a mobile station to a base terminal can e. g. contain a request, if the base station has sufficient resources available to build up the required connection or to transfer user data.
Usually, a random access burst consists of a preamble part and a message part as shown in FIG.
1
. The preamble part may have a length of 1 ms, and the message part may have a length of 10 ms, whereby a time delay is present between the preamble part and the message part.
The random access channel used for the transmission of the random access bursts comprises or consists of succeedingly or periodically provided random access time windows, in which several random access slots are available. The different random access slots are randomly chosen by a communication device for the transmission of random access data. E. g. in a currently proposed wide band direct sequence CDMA (WCDMA) system, the random access channel is based upon an initial preamble spreading code. The spreading code for each cell needs to be planned to ensure that neighboring cells do not use the same preamble spreading code. Within the preamble part of each random access burst, is provided the preamble signature code, which is one of a number of separate codes, i. e. 16, available for use within that cell. These separate preamble signature codes can be seen as separate slots, as indicated in the scheme shown in
FIG. 2
, in which 16 separate preamble signatures are shown as an example. One of these preamble signature codes is chosen randomly by a communication device for the transmission of the preamble part of the random access burst.
Beforehand, the base station or the respective cell controlling unit signals, e. g. over the broadcast control channel, which codes are available in each cell. Additionally, within the time frame for the transmission of a random access burst (10 ms) are provided a number of time offsets, each of 1.25 ms allowing a further 8 variations. In other words, in each time frame a random access time window is provided, a scheme of which is shown in FIG.
2
and which comprises a plurality of random access slots for transmitting random access data. The random access time window thereby extends over a time frame of 10 ms, so that 128 different random access slots (16 separate preamble codes and 8 time offsets) are provided within one random access time windows. It is to be noted that the above-mentioned numbers are only used as examples and other numbers can be chosen depending on system requirements.
The preamble signature code, i. e. the signature code of the preamble part of a random access burst determines the spreading code for the message part of this random access burst. As shown schematically in
FIG. 3
, the preamble signature points to a place in the spreading code tree available for the message part. The message part is then transmitted with this spreading code, e. g. with a spreading factor 16 or 32. Thus, the possibility of collisions between message parts simultaneously transmitted from different communication devices is significantly reduced.
In
FIG. 4
, a sequence of exchanged data between a first communication device, i. e. a user equipment or mobile terminal, and a second communication device, i. e. a cell controller or a base station of the telecommunication system is schematically shown.
The mobile terminal attempting to transmit random access data in the random access channel firstly transmits the preamble part to the base station. The preamble part, as explained above has an allocated unique combination of a preamble signature and a time offset randomly chosen from the available values. Thus, a collision of two preamble parts simultaneously sent from two different mobile terminals to a receiving base station only occurs if the two preamble parts have the same preamble signature and the same time offset. A base station properly receiving a preamble part transmits an acquisition response, e. g. on a downlink common channel, back to the mobile terminal. By means of the acquisition response, the base station signals to the mobile terminal that it is expecting the message part. Then, the mobile terminal transmits the corresponding message part to the base station. In case that the base station does not send an acquisition response, the message part is not sent. The message part contains the random access data. Since the length of the message part is fixed, e. g. 10 ms, the amount of data to be transmitted within one message part is restricted. However, in many cases the size of the message part of the random access burst will be insufficient, so that the random access data to be transmitted have to be segmented over a number of different random access bursts. The transmission of a number of random access bursts is problematic since the transmission is contention-based and there is an increased possibility of collisions when a number of random access bursts is transmitted sequentially. Further, this leads to an undeterminable duration for the random access data transmission. Further, for each random access data segment, a new random access burst has to be formed and to be transmitted. Further, each preamble part has to be successfully received in a receiving device and answered by a positive acquisition response so that the corresponding message part can be transmitted. Then, the random access data of the different message parts transmitted within the different random access bursts have to be reassembled in the receiving device into the complete data set.
The object of the present invention is therefore to provide devices for transmitting and receiving data in a digital telecommunication system and a method for transmitting and receiving random access bursts in a random access channel of a digital telecommunication system, which enable the transmission of a larger amount of random access data in a simple and efficient way.
The above object is achieved by a device for transmitting and receiving data in a digital telecommunication system, in which a random access channel for transmitting random access bursts is provided, with generating means for generating a random access burst comprising a preamble part for acquiring a part of said random access channel and at least one message part for transmitting data in said acquired part of said random access channel, the number of message parts de
Halton John
James Paul
Jürgensen Jens-Uwe
Kornprobst Stefan
Stirling-Gallacher Richard
Frommer William S.
Frommer & Lawrence & Haug LLP
Maung Nay
Persino Raymond
Sony International (Europe) GmbH
LandOfFree
Transmission of random access bursts with at least one... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transmission of random access bursts with at least one..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transmission of random access bursts with at least one... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3121704