An OFDM Based Adaptive Modulation Scheme Employing Variable Coding Rate
| Autor: | Hiroshi Harada, Toshiyuki Nakanishi, Seiichi Sampei, Norihiko Morinaga |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Noise power
Computer Networks and Communications Orthogonal frequency-division multiplexing business.industry Computer science ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS Time division multiple access Signal-to-interference-plus-noise ratio Link adaptation Throughput Data_CODINGANDINFORMATIONTHEORY Code rate Transmitter power output Interference (wave propagation) Power margin Modulation Electronic engineering Electrical and Electronic Engineering Telecommunications business Software Power control |
| Zdroj: | IEICE Transactions on Communications. :526-534 |
| ISSN: | 1745-1345 0916-8516 |
| Popis: | This paper proposes an OFDM based adaptive modulation scheme employing variable coding rate (VCR OFDM AMS), which selects optimum modulation and coding scheme (MCS) realized by combination of several modulation schemes and coding rates. The OFDM AMS with multilevel transmit power control (OFDM AMS/MTPC) can realize high data rate transmission in the dynamic parameter controlled-orthogonal frequency and time division multiple access (DPC-OF/TDMA). The employment of OFDM AMS/MTPC, however, makes transceiver design rather complex. To solve this problem, we propose to improve throughput performances of the OFDM AMS without employment of the MTPC. The simple OFDM AMS, however, does not fully utilize transmit power for throughput improvement because there is surplus transmit power which corresponds to power margin over required signal to interference plus noise power ratio (SINR). Thus, in order to improve transmit power efficiency for throughput increase, we reduce the required SINR gaps between adjacent MCSs by introducing many coding rates. Furthermore, this paper presents an effective bit loading algorithm when multiple coding rates as well as modulation schemes are used. Computer simulation confirms that the proposed VCR OFDM AMS gives sufficient throughput performances as an alternative to the OFDM AMS/MTPC. |
| Databáze: | OpenAIRE |
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