What is a defensive patent?

It is to protect patents that are illegally registered by others

For example, defensive patent portfolios

1. Price of one yuan: Google sold 9 patents to HTC for one yuan .

2. Google can sublicense: Google also requires that it is authorized by HTC (license)

3. Buy-back terms (buy-back): Google has the right to buy back in the future These 9 patents (also use one yuan?).

4. "Against Apple" clause: The only purpose of the agreement is to allow HTC to use these 9 patents to sue Apple

5. Exchange of Apple information