What is modulation and coding scheme?
What is modulation and coding scheme?
Industrial Wireless Tutorials: Modulation and coding schemes (MCS) are used to determine the data rate of a wireless connection using high-throughput orthogonal frequency division multiplexing (HT-OFDM). In a legacy OFDM system, a symbol contains 288 bits, of which 216 are data and 72 are used for error correction.
What is adaptive modulation and why it is important in LTE?
Adaptive Modulation and Coding (AMC) is used to increase the network capacity or downlink data rates. Various modulation types are discussed such as Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM). Spatial multiplexing techniques for 4×4 MIMO antenna configuration is studied.
What is the purpose of adaptive modulation technique?
Adaptive Modulation is a technique which allows a radio to change its speed (modulation rate) as conditions in the radio network change. Interference from outside sources, such as changes in the environment (temperature, tree foliage, moving objects) all effect radio coverage.
What is AMC in LTE?
Long Term Evolution (LTE) is the new upgrade path for carrier with both GSM/UMTS networks and CDMA2000 networks. Adaptive Modulation and Coding (AMC) is used to increase the network capacity or downlink data rates.
How do you calculate coding rate?
The code rate is R = k/n. The Hamming distance d between two codewords is the number of positions by which they differ. For example, the codewords 110101 and 111001 have a distance of d = 2. If valid codewords are always at least a distance d = 2 apart, then it is always possible to detect a single error.
What is modulation in coding?
A coded modulation is a coded communication that is designed against the analog channel over which it is used. Since phase, amplitude, and continuous time play major roles in the analog world, a good coded modulation will tend to work with these.
How does adaptive coding modulation work?
In adaptive coding and modulation (ACM), the modcod for each terminal is adaptively tuned over time to meet the current requirements of the terminal. As channel conditions change, such as the fade varying during a rain and nonrainy period, the modcod adjusts accordingly to become just adequate to compensate.
What is the need of adaptive coding techniques?
Adaptive coding refers to variants of entropy encoding methods of lossless data compression. They are particularly suited to streaming data, as they adapt to localized changes in the characteristics of the data, and don’t require a first pass over the data to calculate a probability model.
How does Adaptive Coding and Modulation work?
Adaptive Coding and Modulation is a statistical, non-static advantage that enables dynamic changes in user throughput. Benefits and value vary over time and are not guaranteed, but are predictable. ACM technology converts link margin to an increase in the data throughput of satellite links.
What is radio channel adaptation?
Link adaptation is a term used in radio communications. This gives a high data througput on the radio channel. If the conditions of the radio channel are poor, a low-level, more robust, modulation scheme is used and the amount of error correction is increased.
Why channel coding is done?
Channel coding is often used in digital communication systems to protect the digital information from noise and interference and reduce the number of bit errors. Channel coding is mostly accomplished by selectively introducing redundant bits into the transmitted information stream.
How is LTE coding rate calculated?
The calculation of LTE code rate is done based on MCS, PRBs and OFDM symbols per slot. The LTE code rate calculator outputs code rate. It takes into account percent of REs used in control channel operation. The PRBs stands for Physical Resource Blocks allocated to the UE by eNB.
What are the benefits of adaptive coding and modulation?
Adaptive Coding and Modulation (ACM) Adaptive Coding and Modulation is a statistical, non-static advantage that enables dynamic changes in user throughput. Benefits and value vary over time and are not guaranteed, but are predictable.
How is adaptive modulation and coding used in HSDPA?
For HSDPA, Adaptive Modulation and Coding (AMC) and hybrid-ARQ must be accounted for in each TTI in which a user is scheduled. In a very simplified simulation, each time a user is scheduled for a TTI, a mean achievable throughput can be calculated for that user given the pathloss and instantaneous fading profile.
What is the purpose of adaptive modulation ( ACM )?
The adaptation is targeted to give each terminal the highest possible data rate that the link will support at those individual terminals, while preserving some operating margin to accommodate short-term fluctuations. In this way, ACM overcomes the limitation of VCM.
How is mean achievable throughput calculated in adaptive modulation?
In a very simplified simulation, each time a user is scheduled for a TTI, a mean achievable throughput can be calculated for that user given the pathloss and instantaneous fading profile. Alternatively, and more commonly, hybrid-ARQ can be explicitly modeled.