Long Term Evolution - LTE - MIMO - Technology and Competitor Landscape Report - Key players, innovators and industry analysis

LTE MIMO standard is being defined by the 3GPP group. As the de-facto standards body, all firms actively participating in the standardization process contribute/declare their patents to the body. The patents contributed to the 3GPP body have to be declared as relevant to (a) the standard and (b) the technical specification within the standard by the contributing company. Step (a) of the declaration citing the relevant standard for the patent is mandatory, failing which the contributing company is not eligible for royalties. Part (b) involving citing the relevant technical specification to which the patent is relevant is voluntary.

The patent contributions to any LTE standard are voluntary and are not screened by the 3GPP body for their relevance to the technical subject. As a result, akin to a gold rush, companies have a strong incentive to disclose as many patents as they have relevant to as many technical specifications as possible. In summary, contributions to a technical specification do not necessarily mean the patents are relevant to the standard.

The gold rush phenomenon increases the information asymmetry between the patent holder and a potential licensee. This information asymmetry creates challenges for companies that sit down to negotiate expensive royalty arrangements subsequent to the commercial roll out of the standard.

It is thus extremely important for a licensee to understand the essential patents in any standard. A standard is an amalgamation of many technical specifications, and one needs to understand the essential patents in each technical specification of the standard.

Dolcera centre for excellence in the electronics and communications domain has identified this problem and as a neutral 3rd party is screening the contributions to the 3GPP body to identify the ‘probably essential’ patents. The Dolcera centre for excellence is working on various technical specifications to identify the ‘essential patents’ for that specification.

The process of identification followed by Dolcera team is as follows - (a) identifying all patent contributions to a technical specification from the 3GPP database (b) screening all the patents for a technical specification for its technical relevance to one of the embodiments of the standard (c) identifying from all the relevant patents, the patents that are essential to a standard’s implementation.

Step (a) has been done by the Dolcera team by collating the patent contributions made to the 3GPP consortium. The step (b) of screening patents has been done by Dolcera team of technical experts by reading through the patents. Dolcera team has spent close to 15 to 20 minutes reading each patent document to determine its relevance to a technical area. And finally step (c) that focuses on identifying whether a technically relevant document is probably essential to the standard or not, has been performed by spending close to an hour on each technically relevant document. In this step the team has done a close comparison of the claims of all relevant documents to the technical implementation steps disclosed in the standard.

This report is a 1st in a series of reports on LTE from the Dolcera team. In this report, Dolcera team has focused on the aspect of MIMO (both Single User and Multi-User) that is considered an essential aspect of LTE advanced standard declared under Release 9 of the 3GPP consortium. MIMO has been considered optional for Release 8 of the LTE standard and Release 9 onwards is considered essential. Dolcera team has for the purpose of this report gone through all the patent contributions made under the various Technical specifications 36.211, 36.212 and 36.213 to determine the patents that are technically relevant to MIMO and more importantly to identify the subset of patents that are ‘probably essential’ to the MIMO implementation under LTE.

Long Term Evolution (LTE)

Long Term Evolution (LTE) systems are designed with an objective of having much higher data rates compared to 3G systems. This is a challenging proposition as wireless networks are subject to interference, multipath and poor propagation channel characteristics that limit data rates.

- MIMO

Lots of recently specified wireless communications standards are ready to support MIMO (Multiple Input Multiple Output) technologies. In Long Term Evolution (LTE), MIMO technologies have been widely used to improve downlink peak rate, cell coverage, as well as average cell throughput. To achieve this diverse set of objectives, LTE adopted various MIMO technologies including transmit diversity, single user (SU)-MIMO, multiuser (MU)-MIMO, closed-loop rank-1 precoding, and dedicated beamforming.

MIMO in LTE (3GPP Release 8)

The basic concept for LTE in downlink is OFDMA (Uplink: SC-FDMA), while MIMO technologies are an integral part of LTE. Modulation modes are QPSK, 16QAM, and 64QAM. Peak data rates of up to 300 Mbps (4x4 MIMO) and up to 150 Mbps (2x2 MIMO) in the downlink and up to 75 Mbps in the uplink are specified.

In Downlink the following transmission modes are possible in LTE:

Single antenna transmission, no MIMO
Transmit diversity
Open-loop spatial multiplexing, no UE feedback required
Closed-loop spatial multiplexing, UE feedback required
Multi-user MIMO (more than one UE is assigned to the same resource block)
Closed-loop precoding for rank=1 (i.e., no spatial multiplexing, but precoding is used)
Beamforming

In LTE, one or two code words are mapped to one to four layers (layer mapper block). To achieve multiplexing, a precoding is carried out (precoding block). In this process, the layers are multiplied by a precoding matrix W from a defined code book and distributed to the various antennas. This precoding is known to both the transmitter and the receiver. In the specification, code books are defined for one, two, and four antennas, as well as for spatial multiplexing (with and without CDD) and transmit diversity.

The Dolcera report for LTE-MIMO is a result of deep analyses of around 1500 patents- the business, the technology, the applications, the players, the alternatives and the future of the market. It provides an extensive analysis and market appraisal of the commercial opportunities open to players in the rapidly expanding. The Dolcera experts went through these patents to identify about 276 patents relevant to the area which were then each analyzed in deeper detail and divided into different technologies in both Single User MIMO and Multi User MIMO. Dolcera has also found the patents which are probably essential for formation of the different standards.

This is the 1st report of its kind now available as a publication from the Dolcera Reports umbrella. The report has been compiled by following best of breed patent analysis practices by a team of experts. The analysis method allows sufficient time by the experts to go through the patents before they are classified into each of the above mentioned categories.

The final report is delivered using a Web2.0 platform. The underlying assumptions of how patents are classified is clearly and transparently laid out - which means that a customer can clearly read the underlying logic of why Dolcera experts believe a patent is probably essential. The entire platform through which the report is presented is extremely flexible in that it allows one to alter the classification of documents if their underlying assumptions are different from the experts.