Method for rendezvous of unlicensed users having multiple transceivers in cognitive radio networks
a cognitive radio network and user technology, applied in the field of cognitive radio network technologies, can solve the problems of unlicensed spectrum not fully utilized, communication is severely congested in unlicensed frequency bands, and the infrastructure of centralized controllers is massively expensive, so as to reduce the time-to-rendezvous and improve the quality of channels
Active Publication Date: 2019-11-14
HOHAI UNIV CHANGZHOU
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AI Technical Summary
Benefits of technology
Ensures rendezvous within a finite time for unlicensed users with any quantity of transceivers, fully utilizing multiple transceivers by running them on different channels and prioritizing better channel quality, improving network performance.
Problems solved by technology
However, fixed spectrum allocation policies become the bottlenecks for more effective utilization of spectrum resources.
A large part of licensed spectrums are not fully utilized in the fixed spectrum allocation policies, whereas communication is severely congestive in unlicensed frequency bands.
However, the centralized controller is a massively expensive infrastructure and its expandability is limited to a certain extent.
In addition, the centralized controller may easily cause a single point failure.
However, since available channels for unlicensed users change with space in cognitive radio networks, it is impractical to achieve rendezvous by using the same common available channel.
In addition, a common control channel is vulnerable to interference and attacks.
When a channel hopping sequence is used to achieve rendezvous, an unlicensed user cannot obtain information about other unlicensed users, and the unlicensed users do not agree on a spectrum to which the unlicensed users are to switch at a time point.
Therefore, it is a huge challenge for design of a rendezvous algorithm.
In addition, distributed heterogeneous cognitive radio networks further face many other challenges in the design of a rendezvous algorithm.
However, in the design of an algorithm, it is assumed that different unlicensed users are equipped with the same quantity of interfaces.
Therefore, the adaptive rendezvous algorithm is not applicable to heterogeneous cognitive radio networks.
However, when one of the unlicensed users is equipped with one transceiver, the maximum time-to-rendezvous in the RPS rendezvous method is infinite.
That is, in this case, two unlicensed users may never rendezvous by using the RPS rendezvous method.
The characteristic of multiple transceivers of an unlicensed user is not fully utilized in the RPS rendezvous method.
It is assumed in the AMRR rendezvous method that each unlicensed user is equipped with more than one transceiver; therefore, the AMRR rendezvous method is not applicable when an unlicensed user is equipped with one transceiver.
In addition, when an unlicensed user uses the AMRR rendezvous method to generate a channel hopping sequence, different transceivers of the unlicensed user may run on the same channel at a time point, and thus the characteristic of multiple transceivers is not fully utilized.
However, the EJS method is only applicable when an unlicensed user is equipped with one transceiver.
However, this method is also applicable only when an unlicensed user is equipped with one transceiver.
Therefore, the problems that generally exist in the methods for rendezvous of unlicensed users in current cognitive radio networks are as follows:
1. In most articles, it is considered that an unlicensed user is equipped with only one transceiver. That is, the unlicensed user can run on only one available spectrum at a time point, and the time-to-rendezvous is relatively long.
2. In most articles concerning that an unlicensed user is equipped with multiple transceivers, it is only considered that an unlicensed user is equipped with more than one transceiver. However, in heterogeneous cognitive radio networks, an unlicensed user may be equipped with different quantities of transceivers, including only one transceiver. When an unlicensed user is equipped with one transceiver, the rendezvous method is no longer applicable.
3. Multiple transceivers of an unlicensed user are not fully utilized. In most rendezvous methods, different transceivers of one unlicensed user may run on the same channel at a time point. The multiple transceivers are not utilized more effectively to reduce the time-to-rendezvous.
4. In most articles, the same channel quality is assumed in the design of a channel hopping sequence. However, in an actual communication environment, the channel quality may be different.
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[0054]The present invention is further described in detail below with reference to the accompanying drawings.
[0055]As shown in FIG. 1, a method for rendezvous of unlicensed users having multiple transceivers in cognitive radio networks according to the present invention mainly includes four stages.
[0056]The first stage is an initial stage: setting an initial environment for the method for rendezvous of unlicensed users; and setting an initial timeslot t=1, randomly selecting an initial channel index i0 from [1, |Ca|], randomly selecting one channel index value less than P from Ca as a hopping interval s, and arranging Ca and N in order according to channel quality, where N={c1, c2, . . . , C|N|} is a licensed channel set, Ca ∈ N is an available channel set of an unlicensed user a, |Ca| is the quantity of available channels of the unlicensed user a, and P is a minimum prime number not less than the quantity of licensed channels |N|.
[0057]The second stage is a stage of selecting a ren...
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The present invention discloses a method for rendezvous of unlicensed users having multiple transceivers in cognitive radio networks, including four stages: an initial stage: setting an initial communication environment; a stage of selecting a rendezvous method: selecting a method for generating a channel hopping sequence according to the quantity of transceivers; a stage of generating a channel hopping sequence: using a single-transceiver rendezvous method or a multiple-transceiver rendezvous method to generate a channel hopping sequence; and a rendezvous stage: running, by an unlicensed user, on a corresponding channel and attempting to rendezvous with a destination node of the unlicensed user, where if rendezvous is achieved, the rendezvous process ends; and if rendezvous is not achieved, the rendezvous process continues until rendezvous is achieved. By using the present invention, the problem of rendezvous of unlicensed users equipped with different quantities of transceivers in heterogeneous cognitive radio networks is effectively resolved.
Description
BACKGROUND OF THE INVENTIONField of the Invention[0001]The present invention relates to cognitive radio network technologies, and in particular, to a method for rendezvous of unlicensed users having multiple transceivers in cognitive radio networks.Description of Related Art[0002]In recent years, with the rapid development of wireless devices and applications in unlicensed frequency bands, the requirements for unlicensed spectrums grow vigorously. However, fixed spectrum allocation policies become the bottlenecks for more effective utilization of spectrum resources. A large part of licensed spectrums are not fully utilized in the fixed spectrum allocation policies, whereas communication is severely congestive in unlicensed frequency bands. To utilize spectrum resources more effectively, cognitive radio technologies emerge accordingly. In cognitive radio networks, unlicensed users can use licensed spectrums without interfering with normal communication of licensed users.[0003]Before ...
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IPC IPC(8): H04B1/7143H04W16/14
CPCH04B1/7143H04W16/14H04B17/382H04B1/713H04W16/10
InventorHAN, GUANGJIELI, AOHAN
OwnerHOHAI UNIV CHANGZHOU