Patents on cognitive radio over TVWS

At the beginning of the year I wrote a post about the companies with most patents on cognitive radio. In that 1st quarter of 2010 the three leading companies in number of patents were¹ Motorola (14%), Samsung (14%) and Qualcomm (8%).

A recent survey shows the patent scenario for the last quarter, now focused on cognitive radio patents for the television band (TVWS). The results are very similar to the previous post and only the order of the three leading companies has changed. Samsung Electronics leads in number of patents related to cognitive radio over TVWS, followed by Motorola, and Qualcomm. While the quality of several of these patents is doubtful, it is true that usually exists certain correlation between the number of patents and the actual innovations developed by a certain company.

Patent: Signal Detection in Cognitive Radio Systems

After writing the post about the companies with most patents on cognitive radio I wondered how innovative these patents could be. To check it I present here one of the lastest patents filed by Motorola related to spectral sensing: US20100081387: Signal detection in cognitive radio systems.


The first claim, the soul of the patent, reads like that:

A method, with a cognitive radio wireless device, for dynamically managing signal detection in a cognitive radio system, the method comprising:

• performing spectrum sensing for a first sensing frame on at least one communication channel;
• receiving, in response to performing spectrum sensing, at least one observed signal on the at least one communication channel;
• and performing a detection decision to determine if the observed signal is one of noise and an active signal associated with an active user, wherein performing the detection decision comprises:
  1. determining an energy estimation .epsilon. associated with the at least one observed signal;
  2. comparing the energy estimation .epsilon. with a current detection threshold, wherein the current detection threshold is one of an arbitrarily defined threshold and a detection threshold based on a previous detection decision for a sensing frame immediately prior to the first sensing frame;
  3. setting, in response to the energy estimation being above the current detection threshold, a first new detection threshold equal to the current detection threshold;
  4. and setting, in response to the energy estimation .epsilon. being below the current detection threshold, a second new detection threshold as a function of the current detection threshold and the energy estimation .epsilon.;
  wherein one of the first and second new detection threshold is used for at least one subsequent detection decision for at least a second sensing frame."

That is, they use energy detection in a given channel by comparing the meassured energy with a threshold that is updated in the case that the channel is decided as vacant.

A patent by definition

must be innovative to the point that it wouldn't be obvious to others."

Then my question is if updating the threshold after non-detection of a primary user is innovative enough in order to justify a patent, or most of these patents are just for the future work of their lawyer's offices.

Patents related to Cognitive Radio

If you wonder who is taking positions in the upcoming fight for the future Cognitive Radio standards just take a look to this chart showing the patents related to cognitive radio approved in the first quarter of 2010 by Tech & IP. The three leading companies in number of patents are Motorola (with 14% of the patents), Samsung (14%) and Qualcomm (8%):

While Motorola is one of the greatest contributors of cognitive radio research (with numerous technical contributions in IEEE DySPAN, European End-to-End Reconfigurability Project, SDR Forum, ...) most of its work was about integrating next generation “cognitive” handsets into current telecommunication infrastructure. On the other hand Samsung actively participated into the development of the elaboration of the IEEE 802.22 proposal, first CR-oriented standard. Its efforts focused mainly on pushing their spectrum sensing technologies. While Qualcomm is yet focused on the development of LTE, it is also taking positions with its patents on cognitive radio.