Apparatus for generating a set of radio parameters, a transmitter and a receiver

a technology of radio parameters and apparatus, applied in the direction of channel coding adaptation, transmission path division, wireless communication, etc., can solve the problems of inability to determine a single type of guard interval optimized under various communication environments, adverse effect on such a mobile station, and high workload. achieve the effect of improving information transmission efficiency

Inactive Publication Date: 2009-12-03
NTT DOCOMO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0015]According to an embodiment of the present invention, it is possible to improve information transmission efficiency in an OFDM mobile communication system.

Problems solved by technology

However, the guard interval includes only part of the effective symbol, and thus a larger period of the guard interval is not preferable from the viewpoint of information transmission efficiency.
Therefore, it is impossible to determine a single type of guard interval optimized under various communication environments.
However, signal processing corresponding to such various symbol formats leads to an extremely heavy workload, which is unfavorable for mobile stations with a relatively simple configuration.
For a mobile station having no option of an operating frequency (clock frequency), available signal processing is strictly limited, and thus the aforementioned problem may have a particularly adverse effect on such a mobile station.

Method used

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  • Apparatus for generating a set of radio parameters, a transmitter and a receiver
  • Apparatus for generating a set of radio parameters, a transmitter and a receiver
  • Apparatus for generating a set of radio parameters, a transmitter and a receiver

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Effect test

first embodiment

[0076]Although a system employing OFDM (Orthogonal Frequency Division Multiplexing) for downlink communications is described in the following embodiment, the present invention is also applicable to other multi-carrier systems.

[0077]FIG. 3 shows a (first) block diagram for illustrating a transmitter in accordance with one embodiment of the present invention. Although this transmitter is typically included in a base station, the same transmitter may be also included in a mobile station. A base station includes ND data channel processing units 302-1 to 302-ND, a control channel processing unit 304, a multiplexing unit (MUX) 306, an Inverse Fast Fourier Transform (IFFT) unit 308, a guard interval insertion unit 310, a digital to analog (D / A) conversion unit 312, a symbol parameter adjusting unit 320, and a TTI adjusting unit 321. The ND data channel processing units 302-1 to 302-ND mutually have the same configuration and function, and the data channel processing unit 302-1 is represent...

second embodiment

[0110]Next, a set of symbol parameters and deriving method thereof in the symbol parameter adjusting units 320 (FIG. 3) and 542 (FIG. 5) are described below. The set of symbol parameters defines the subcarrier interval, the sampling frequency, the period of the effective symbol, the period of the guard interval, the number of symbols in a single TTI, and so on. It should be noted that all of the parameters cannot be determined independently. For example, the subcarrier interval and the period of the effective symbol have a reciprocal relationship with each other. Also, the period of a single TTI is derived by multiplying the period of one symbol (total period of the guard interval and the effective symbol) with the number of symbols. Three methods of deriving a second set of symbol parameters from a first set of symbol parameters are described below.

[0111]First, as shown in FIG. 9(A), assume that the first set of symbol parameters is determined as follows.

[0112]subcarrier interval=2...

third embodiment

[0183]According to the first embodiment, the length of the transmission time interval (TTI) is adjusted. According to the second embodiment, the length of the guard interval and / or the effective symbol is modified. These embodiments may be used independently or used in combination as described below.

[0184]First, as shown in FIG. 11(A), assume that the first set of symbol parameters is determined as follows. These parameter values are the same as those in FIG. 9(A), except that the period of one TTI is extended from 0.5 ms to 1.0 ms.

[0185]subcarrier interval=22.5 kHz

[0186]the total number of subcarriers=200

[0187]sampling frequency=5.76 MHz=3 / 2*3.84 MHz

[0188]period of effective symbol=256 samples (44.4 μs)

[0189]period of guard interval=32 samples (5.5

[0190]period of one symbol=288 samples (guard interval+effective symbol)

[0191]loss rate=32 / 288=11.1%

[0192]the number of symbols in one TTI=20

[0193]period of one TTI=1.0 ms

[0194]period of one frame=10 ms

[0195](1) A first method of deriving...

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Abstract

A transmitter includes: a data modulation and channel coding unit configured to perform data modulation and channel coding for a data channel with a modulation level and a channel coding rate updated for each transmission time interval; a multiplexing unit configured to multiplex a control channel and the data channel for each transmission time interval; and an adjusting means configured to adjust a length of the transmission time interval. Increasing a unit of information transmission in the time direction and/or the frequency direction depending on communication conditions can reduce a frequency of inserting (allocating) the control channel, and can improve data transmission efficiency.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an apparatus for generating a set of radio parameters, a transmitter, and a receiver.[0003]2. Description of the Related Art[0004]In the mobile communication systems where video and / or data are mainly communicated, there is need of a much higher capability than in the conventional mobile communication systems (IMT-2000), and a higher capacity, a faster speed, and a broadband connection have to be achieved. In these systems, it is expected that they will be used under various communication environments such as indoor and outdoor areas. Under the outdoor areas, multiple cells (multi-cell) covering a wide area are provided for enabling fast packet transmission for a fast-moving mobile station. Under the indoor areas, because radio waves are attenuated more drastically, access points are provided within buildings without support of radio communications at outdoor base stations. From other vi...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H04L27/28H04W28/00H04W28/18
CPCH04L1/0003H04L1/0007H04L1/0009H04W84/042H04L27/2607H04L5/0007H04L27/2602H04L27/2603
Inventor SAWAHASHI, MAMORU
Owner NTT DOCOMO INC
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