Privacy Policy

Effective: 2026-10-13 · Last updated: 2026-11-02

This site, okwujun.pw ("this site", operated by Router CSI Lab), is a technical research and tutorial site about Wi-Fi CSI. The legacy csi.okwujun.pw host remains available for compatibility while the root domain is the canonical address. This policy explains what data we touch when you visit, why, and what you can do about it.

The short version

This is a static website: no accounts, no logins, no comment section, no submission forms, and no selling of data. We never ask you for personal information. Data is only generated through hosting and security logs, privacy-first aggregate analytics, and third-party advertising services.

1. What we collect

1.1 Information you give us

There is exactly one case: you send us an email (a correction, a contribution, a business enquiry). We then see your email address and your message, and we use them only to answer that matter.

1.2 Information generated by visiting

This site is hosted on Cloudflare Pages. Any web visit produces ordinary server logs, which may include your IP address, User-Agent (browser and OS), the pages requested, the referring page and a timestamp. Those logs are handled by the hosting provider under its own policies; we do not use them to identify you.

1.3 What we deliberately do not collect or do

• no registration or login, so we hold no accounts or passwords;
• no comments, guestbook or contact forms, so we hold no submitted form data;
• we never sell, rent or trade personal information;
• no collection of precise location, contacts, photos or files;
• the in-page demos (CSI heatmap / Doppler playback) run entirely in your browser — nothing you select there is uploaded to a server.

2. Cookies and similar technologies

Cookies are small pieces of text a site can store in your browser. This site sets no cookie of its own that identifies you. Cookies you may encounter come from third-party advertising services and are used to:

• remember content you have already seen and limit how often the same ad repeats;
• measure how ads and pages perform;
• show more relevant ads, where you have consented to that.

You can clear or block cookies at any time in your browser settings. Blocking third-party cookies does not affect the articles, tutorials, dataset downloads or the interactive demos on this site.

3. Advertising: Google AdSense

This site shows ads through Google AdSense to cover hosting and domain costs. Ads are served by Google and its partners; they do not pass through our servers, and we have no access to the personal data the ad service collects.

The specific facts you should know:

1. Third-party vendors, including Google, use cookies to serve ads based on your prior visits to this and other websites;
2. Google's use of advertising cookies (including the former DoubleClick cookie) enables it and its partners to serve ads based on those visits;
3. You can turn off personalised advertising in Google Ads Settings: https://adssettings.google.com/
4. You can also opt out across many vendors at once with industry tools:
   • Digital Advertising Alliance: https://optout.aboutads.info/
   • European Interactive Digital Advertising Alliance: https://www.youronlinechoices.com/uk/your-ad-choices
5. Google's own explanation of how it uses information from sites that use its services: https://policies.google.com/technologies/partner-sites
6. Google's privacy policy: https://policies.google.com/privacy

For users in the EEA and the UK: your consent is required before personalised advertising is shown. This site uses Google's consent management tool (AdSense → Privacy & messaging) to collect and record that consent, and you can change your choice in that prompt at any time. Declining personalised ads does not restrict your access to any part of this site.

If you would rather not be tracked by advertising cookies at all, the most reliable route is to block third-party cookies in your browser or use an ad-blocking extension — the content and downloads here work fine either way.

4. Analytics

This site uses Cloudflare Web Analytics, Cloudflare's privacy-first real-user-monitoring service, to understand page-load performance and aggregate traffic. The page loads Cloudflare's analytics beacon from https://static.cloudflareinsights.com/beacon.min.js, and measurements are sent to this site's /cdn-cgi/rum endpoint.

Cloudflare documents that this service collects the minimum amount of information - timing metrics - needed to show website performance; that it does not collect or use visitors' personal data; and that it does not track individual end users across its customers' Internet properties. The dashboard we use may show aggregate dimensions such as country, host, path, referrer, device type, browser, operating system and navigation type. Cloudflare also states that its Web Analytics service does not log query strings. We use this reporting to understand and improve site performance; we do not use it to identify individual visitors or to build advertising profiles.

Cloudflare processes this data under its own privacy policy. For verification, see Cloudflare's official Web Analytics overview, data collection description and privacy policy.

5. Hosting and third-party services

External links in our articles (paper DOIs, open-source repositories, shops) lead to third-party sites. Once you leave this site, their privacy policies apply; we do not control them and are not responsible for them.

6. On-site data and downloads

We publish Wi-Fi CSI sample data and tooling under open licences such as CC BY 4.0:

• these files are de-identified, but they are not guaranteed to be legally anonymous against every attacker, linked dataset and time horizon;
• transmitter MAC addresses are replaced with 02:00:00:00:00:01;
• the current public releases retain outer absolute timestamps and behavioural patterns, so they are more accurately described as pseudonymised or de-identified data;
• downloading them transmits nothing personal from you — the request only touches the host's ordinary logs.

See Wi-Fi CSI privacy and dataset de-identification for the threat model, residual data and rules for a future time-shifted release.

7. Data retention

• emails: kept until the matter is resolved, then archived or deleted according to our mail provider's normal practice;
• server logs: retained briefly by the hosting provider under its policy; we keep no separate copy;
• Cloudflare Web Analytics: Cloudflare states that unsampled beacon data is retained for seven days and then aggregated to around 10% of the original volume for long-term storage;
• advertising and cookie data: retained by Google under its own policies — we cannot access or delete it.

8. Your rights

Depending on where you live, you may have some or all of the following rights:

• access and correction — learn whether we hold information about you and ask us to correct it;
• deletion — ask us to erase your personal information;
• objection / restriction — object to processing based on legitimate interests, or ask us to restrict it;
• withdraw consent — withdraw consent for consent-based cookies/ads at any time (see the opt-out links in section 3);
• portability — receive the data you provided in a structured format;
• complaint — lodge a complaint with your local supervisory authority.

The main regimes involved are the EU/UK GDPR, California's CCPA/CPRA, and China's PIPL.

Because this site stores no accounts and no form data, most requests in practice concern third-party providers (such as Google). We will do our best to point you to the right channel. To exercise any of these rights, use the email address below.

9. Children's privacy

This site is aimed at adult technical readers and researchers, not at children, and we do not knowingly collect personal information from children. If you believe a child has provided personal information to us, email us and we will delete it promptly.

10. Security

The whole site is served over HTTPS with HSTS; it is a set of static files, so there is no database or user credential store to breach. That said, no transmission over the internet can be guaranteed to be perfectly secure.

11. Changes to this policy

If our practices change (changing analytics, ad networks or site features), we will update this page and revise the "Last updated" date above. Material changes will be flagged on the home page or the relevant page. Continuing to use the site means you accept the updated policy.

12. Contact

For any question, request or complaint about this policy:

Email: okwujun@gmail.com

We normally reply within 7 business days.

Related: About this site · Methodology and evidence grading · Dataset and licence