EP 3 353 901 B1 relates an apparatus and method for scrambling control field information for wireless communications.
Brief outline of the case
The OD revoked the patent as the claims as granted infringed Art 123(2). Some AR were also infringing Art 123(2) or were not compliant with Art 84, or were not admitted.
During the appeal proceedings, both opponents withdrew their oppositions.
The board decided that the patent as granted lacked N overD1=US 2015/0117433.Some AR lacked N or IS over D1 and only two requests were held to be infringing Art 123(2).
Only claim 1 as granted will be discussed.
At stake are:
Feature 1.2.1.3
modulating the interleaved HE-SIG-B bits to generate N modulated symbols, N being a positive integer,
Feature 1.2.1.4
generating N phase-rotated symbols by applying a scrambling sequence to the N modulated symbols, wherein the scrambling sequence is for reducing peak-to-average power ratio (PAPR) occurring within the 20 MHz HE-SIG-B unit of the HE-SIG-B field
The proprietors’ point of view
The proprietors submitted that D1 addressed a different problem, taught a different solution and failed to disclose at least certain features.
Feature 1.2.1.3
The number of modulated symbols obtained after the “constellation mapper” of D1 was not the same as the number of phase-rotated symbols after the PAPR reduction.
Feature 1.2.1.4
D1 did not disclose scrambling of “modulated symbols” because the input of the “PAPR reduction” was the output of the “block coder”, which comprised “copies of the modulated symbols” and not the “modulated symbols” themselves. Moreover, document D1 applied “phase shifts” to whole blocks, without any mention of a “scrambling sequence”.
The board’s decision
Although present claim 1 does not indicate to which type of data communication unit the generated “HE PPDU frame” is eventually transmitted, the board assumed, in the proprietors’ favour, that the claimed “frame” is supposed to be sent to a data receiving unit that is indeed capable of properly decoding, deinterleaving, demodulating and descrambling the respective data fields of the transmitted “frame” – in a mirrored way -at the receiver side.
Feature 1.2.1.3
The board did not agree with the proprietors’ construction of “modulation”. In the board’s view, “modulating” may encompass further actions beyond “constellation mapping”.
Such interpretation is also in line with the patent description (see paragraph [0123]: “[…] the modulation operation 2310 may comprise constellation mapping”). The board thus sees no (technical) reason to exclude “block coding” from such “modulation operation”.
Feature 1.2.1.4:
The “scrambling sequence” according to present claim 1 does not necessarily imply a “per-symbol sequence”, but even if it did, paragraph [0172] of D1 enumerates concrete per-symbol “phase shifts” which amount to “scrambling sequences” in the claimed sense.
This is because “phase shifts” introduced by the “PAR reduction unit” have to be length-matched to the 48 symbols at the output of the “block coder” to obtain the “resulting sequences”.
Hence, the subject-matter of claim 1 as granted was not new in view of D1.
Comments
Application of G 1/24
Without mentioning G 1/24, it is manifest that the board “consulted” the description.
For feature 1.2.1.3, it allowed the board to conclude that, after consultation of the description that the feature “modulation” in the claim had to receiver a broader interpretation than that resulting from its plain wording. In this respect, is actually confirms T 1849/23, also commented in the present blog.
In respect of feature, 1.2.1.4, consulting the description also allowed to identify an identical feature in the claim and in D1.
On the procedure
The patent EP 3 353 901 B1 is classified inH04W 84/12, H04L 27/26, H03M 13/27, and H04L 25/03.
The ISR carried out by the USPTO indicates as search fields H04L 27/26; H04B 1/7176; H04W 84/12; H03M 13/27.
The search field in the SESR is indicated as H04L.
D1=US 2015/0117433 bears the classification units H04W84/12, H04L27/26 and H04L29/06.
It is thus surprising that neither the ISR nor the SESR have revealed D1.
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