Article 1 1 of the Patent Law stipulates that "after the patent right for invention and utility model is granted, no unit or individual may exploit its patent without the permission of the patentee, that is, it may not manufacture, use, promise to sell, sell or import its patented products for production and business purposes, nor may it use its patented methods and use, promise to sell, sell or import products directly obtained according to the patented methods.
This shows that the patent right is an exclusive right, that is, others exploit the patented technology without the permission of the patentee and infringe on the patentee's patent right. Frankly speaking, the patent right only restricts the rights of others, that is, it does not allow others to implement it, but it does not necessarily guarantee that it has the right to implement it. The simplest example is that if your patent is further developed based on other people's patented technology, you can't implement it without the permission of the previous patentee.
Of course, you can't help it. You can apply to the former patentee for an implementation license. If he doesn't allow it, you can also apply for cross-licensing according to Article 5 1 of the Patent Law, that is, you and the previous patentee allow each other to exploit each other's patents, so that you can win-win cooperation.
In order to avoid patent technology infringement, it is very necessary to search and investigate patents in related technical fields before implementation. Because patent is an interdisciplinary business integrating technology and law, it is highly professional, so I suggest you find a professional patent agency for consulting and entrusting business when you have sufficient funds. If you don't have enough money, ask more friends and learn more relevant legal knowledge yourself, which may make do.