Opportunistic channel accessing and switching method and device
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A channel access and opportunity technology, applied in wireless communication, using the return channel for error prevention/detection, electrical components, etc., can solve the problems of channel link quality deterioration, transmission opportunity loss, frequency domain transmission opportunity waste, etc.
Active Publication Date: 2013-06-12
WUXI TSINGHUA NAT LAB FOR INFORMATIONSCI & TECH INTERNET OF THINGS TECH CENT
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In fact, since the channel correlation time is only a statistical measure of the duration of highly correlated channel quality, the actual time for the channel to maintain a good state may be far beyond the channel correlation time, and at the same time, the channel quality may also be within a channel correlation time rapid deterioration
Therefore, using a constant transmission time will lead to the loss of transmission opportunities in both time and frequency: the current channel state is stil
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Embodiment 1
[0076] A method for opportunistic channel access and switching, comprising:
[0077] The receiving end receives the RTS data packet containing the training sequence sent by the sending end through the detected idle channel; obtains the channel state of the idle channel according to the training sequence, and feeds back the channel state to the sending end through CTS, and the sending end Judge with the receiving end whether the channel state is greater than or equal to the optimal threshold k * , if yes, then access the idle channel to transmit the data stream; otherwise, the sender and receiver switch channels according to the shared channel detection order, and search for and detect the next idle channel.
[0078] In this embodiment, accessing the idle channel for data stream transmission further includes:
[0079] The data stream is divided into multiple data packets and transmitted sequentially, and the training sequence is embedded at the end of each data packet while tr...
Embodiment 2
[0143] In this embodiment, the transmission system is a wireless transmission system in the 500MHz frequency band, and the channel bandwidth is 2MHz; the maximum Doppler frequency shift of the system is 15Hz (that is, the maximum relative moving speed ); the average received signal-to-noise ratio γ 0 =10dB; the duration of each data frame τ d is 1ms; the time spent on channel switching τ S 0.15ms; channel detection packet interaction time τ R is 0.35ms; the time spent on channel monitoring τ m is 0.05ms; the system has 10-level modulation and coding rate, that is, K=10, and the rate interval is 1Mbps, that is, the transmission rate is 1~16Mbps, assuming an ideal signal-to-noise ratio-rate model, that is, R(k)=Blog 2 (1+Γ k )bps, then the signal-to-noise ratio threshold Γ 0 =0,Γ 10 =∞, [Γ 1 ,Γ 2 ,…,Γ 9]=[-3.8,0,2.6,4.8,6.7,8.5,10.1,11.8,13.4]dB.
[0144] First get the channel distribution:
[0145] Depend on π k = ...
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Abstract
The invention relates to the field of access control in a wireless communication technology, in particular to an opportunistic channel accessing and switching method and device. The method comprises the following steps of: receiving, by a receiving end, an RTS (Request To Send) data packet comprising a training sequence transmitted by a transmitting end through a detected idle channel; acquiring a channel state of the idle channel according to the training sequence; judging whether the channel state is greater than or equal to optimal threshold k*; and if the channel state is greater than or equal to the optimal threshold k*, accessing to the idle channel to perform transmission of a data stream, and otherwise, switching the channel by the transmitting end and the receiving end according to a shared channel detection sequence, and searching and detecting a next idle channel. According to the method and the device, a user can obtain the channel state according to the training sequence, adjust the accessing and the switching of the channel and maximally utilize the instantaneous transmission opportunity of the channel in time-frequency two dimension, so that the utilization efficiency of the channel is improved; diversity utilization is performed on a link layer; and compared with the conventional physical layer diversity technology, extra accessory hardware is not required, and the conventional communication equipment is favorably applied.
Description
technical field [0001] The invention relates to the field of access control in wireless communication technology, in particular to an opportunistic channel access and switching method and device. Background technique [0002] Improving the transmission efficiency of wireless spectrum is a classic research topic in the field of wireless communication. One of the key issues to be faced is the time-varying characteristics of wireless channels: due to the multi-path propagation characteristics of wireless signals, there are reflective objects in the communication terminal or surroundings. In mobile application scenarios, the quality of signals received by terminals changes dynamically over time. Traditional signal processing methods, such as physical layer technologies such as equalization, coding, and diversity combining, are effective in combating channel dynamics, and alleviate the adverse effects of channel dynamics on data packet transmission to a certain extent. However, t...
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IPC IPC(8): H04W74/08H04L1/16
Inventor 李柏文杨盘隆刘怡静杨磊刘云浩
Owner WUXI TSINGHUA NAT LAB FOR INFORMATIONSCI & TECH INTERNET OF THINGS TECH CENT
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