Pulse or digital communications – Testing – Data rate
Patent
1997-08-28
2000-12-26
Pham, Chi H.
Pulse or digital communications
Testing
Data rate
370232, 370252, H04B 346, H04B 1700, H04Q 120
Patent
active
061670790
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for identifying data transmission rate from a signal which has several transmission rate alternatives and which comprises modulation symbols which are formed as a vector and which are submatrices of a previously known, essentially orthogonal transform matrix selected on the basis of a combination of bits to be transmitted in which method a correlation is formed between a received modulation symbol and the previously known modulation matrix, as a result of which a correlation vector is produced which comprises correlation values and by means of which a signal is detected.
The present invention further relates to a receiver receiving a signal which has several data transmission rate alternatives and which comprises modulation symbols which are formed as a vector and which are submatrices of a previously known, essentially orthogonal transform matrix selected on the basis of a combination of bits to be transmitted which receiver is arranged to form a correlation between a received modulation symbol and the previously known modulation matrix, as a result of which a correlation vector is produced which comprises correlation values and by means of which a signal is detected.
BACKGROUND OF THE INVENTION
The advance of CDMA technology has brought about new ways of using more effectively radio frequencies on the whole spectrum, which in comparison to TDMA and FDMA systems provides a possibility for a greater number of users per a frequency channel, for example, a faster power regulation, a more effective use of data transmission rates and a better connection between a base station and a subscriber terminal equipment. The possibility to use different data transmission rates in the subscriber terminal equipment adds to the capacity of the system as when a speech connection is not in use or when the amount of data to be transferred is small, the capacity of the cellular radio system can be increased at a smaller data transmission rate, interference being diminished for other users. In future CDMA standards, data transmission rate can be changed specifically for each frame on the basis of speech activity so that the rate in a single data transmission frame is the same, while a frame generally comprises 16 transmission time slots.
The data transmission rates to be transmitted, of which there are typically four, are divided at random to said sixteen different transmission time slots on the basis of a long spreading code, whereby the greatest data transmission rate (e.g. 9,600 kbps) uses all 16 time slots, when the data transmission rate is half of the greatest data transmission rate, eight time slots out of sixteen are used, when the data transmission rate is fourth of the greatest data transmission rate, four time slots out of sixteen are used, and the smallest data transmission rate is eighth of the greatest data transmission rate and only two time slots out of sixteen transmission time slots are in use.
In the base station the transmission time slots used by all the data transmission rates can be calculated and detected when the used long spreading code is known. Different data transmission rates also share a feature that all the transmission time slots of the next smallest data transmission rate by one are the same (that is, the greatest data transmission rate has eight of the same transmission time slots as a lower data transmission rate.)
When different data transmission rates are being used, the base station should identify the transmitted data transmission rate, which is not very easy. Various interferences and fadings in the radio channel make the identification of the data transmission rate difficult and it is difficult to calculate the data transmission rate from all data transmission rates to Viterbi decoding and a complicated equipment is required for it. In prior art solutions, a parallel Viterbi decoding is used separately for each data transmission rate. In that case the possible calculated information of a received signal on the data tr
REFERENCES:
patent: 4584694 (1986-04-01), Gumacos
patent: 4887280 (1989-12-01), Reisenfeld
patent: 5396516 (1995-03-01), Padovani et al.
patent: 5524122 (1996-06-01), Lepitre et al.
patent: 5619524 (1997-04-01), Ling et al.
patent: 5771226 (1998-06-01), Kaku
Keskitalo Ilkka
Kinnunen Pasi
Corrielus Jean B
Nokia Telecommunications Oy
Pham Chi H.
LandOfFree
Method for identifying data transmission rate, and a receiver does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for identifying data transmission rate, and a receiver, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for identifying data transmission rate, and a receiver will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1003213