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What are the orthogonal codes?
Truly orthogonal codes: Two codes are said to be orthogonal if when they are multiplied together the result is added over a period of time they sum to zero. For example a codes 1 -1 -1 1 and 1 -1 1 -1 when multiplied together give 1 1 -1 -1 which gives the sum zero.
Which technology uses orthogonal codes?
Spread spectrum systems trade bandwidth for processing gain, and code division systems use a variety of orthogonal or almost orthogonal codes to allow multiple users in the same bandwidth. Thus, CDMA systems can have a higher capacity than either analog or time division multiple access (TDMA) digital systems.
What is orthogonal CDMA?
CDMA (Code Division Multiple Access) is a communication technique that allows multiple users to communicate simultaneously over one frequency. This is achieved through the use of spreading codes, whereby a single data bit is “spread” over a longer sequence of transmitted bits. Such codes are known as orthogonal codes.
What is an orthogonal cover code?
Orthogonal cover codes are length-2 Walsh codes extended over the two DM RS in the subframe as shown in Figure 7.4. OCCs provide two benefits: they improve the reliability in separating the different RS from each other, especially when SU-MIMO or MU-MIMO transmission contains several transmission layers.
Which code is used in CDMA?
IS-95 CDMA Standard uses three types of codes namely 1) Long code 2) Short code and 3) Walsh Hadamard codes.
What is orthogonal cover code?
What is the use of orthogonal codes in is 95 CDMA one standard?
This pseudo orthogonal property is used in IS-95 reverse link in a 1.2288Mcps chip sequence to differentiate between mobiles. On the forward link the long code is decimated down to a 19.2kbps bit stream for a unique user mask.
What is the frequency of CDMA?
The band used in CDMA is 824 MHz to 894 MHz (50 MHz + 20 MHz separation). Frequency channel is divided into code channels. 1.25 MHz of FDMA channel is divided into 64 code channels.
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