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`Exhibit A
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`APPENDIX D: DSSS SIGNAL
`I understand that the Court has construed the term “random access signal” in claims
`1.
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`1, 2, 4, and 6–9 of the ’908 patent as “a direct sequence spread spectrum signal used as a random
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`access signal.”
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`Dkt. No. 198 (“Claim Construction Order”) at 54.
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`2.
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`I also understand that the Court has construed the term “probing signal” in claims
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`23, 24, 26, & 28 of the ’302 patent to mean “a direct sequence spread spectrum signal used as a
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`probing signal.”
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`Claim Construction Order at 81.
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`3.
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`I also understand the Court relied on the specification’s use of DSSS signal when
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`providing this construction.
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`Claim Construction Order at 57.
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`1.
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`DSSS SIGNAL IN THE ASSERTED PATENTS’ SPECIFICATIONS
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`4.
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`The shared specification of the ’908 Patent and ’302 Patent provides examples of
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`a DSSS Signal used as a random access signal. For example:
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`’908 patent 8:49–55.
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`2
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`5.
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`The shared specification of the ’908 Patent and ’302 Patent provides examples of
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`a DSSS Signal used as a probing signal.
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`’908 patent 5:35–39.
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`’908 patent 9:62–64
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`6.
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`A person of ordinary skill in the art understands that probing signals do not
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`contain any information. Instead, probing signals are typically used for channel probing. This
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`understanding is reflected in several publications such as the following excerpts:
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`7.
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`The shared specification of the ’908 Patent and ’302 Patent provides
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`embodiments where the DSSS signal is an unmodulated DSSS sequence or a DSSS sequence
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`modulated by one.
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`8.
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`For example, the specification provides an embodiment where the DSSS signal is
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`formed from modulating a DSSS sequence with information bits that are always one.
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`3
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`See, e.g., ’908 patent at 2:58–3:3.
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`9.
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`As another example, the specification provides an embodiment where the DSSS
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`signal is formed from an unmodulated DSSS sequence where the modulation symbol is one.
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`See, e.g., ’908 patent at 4:58–62.
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`10.
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`Thus, a person of ordinary skill in the art would understand that a DSSS signal
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`includes unmodulated DSSS sequences or DSSS sequences modulated by one.
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`11. Moreover, in implementation, there is no difference between transmitting or
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`receiving an unmodulated DSSS sequence and a DSSS sequence modulated with information
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`bits of one.
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`2.
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`DSSS SEQUENCE IN THE ASSERTED PATENTS’ SPECIFICATIONS
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`4
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`12.
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`The specification also provides qualities about the DSSS sequence used in a
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`DSSS signal. For example, the ’908 patent includes a section titled “DSSS Signal Design” that
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`teaches that DSSS sequences are chosen to have good autocorrelation and cross-correlation
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`properties.
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`’908 patent at 7:25–29.
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`13.
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`The DSSS Signal Design portion of the specification also discusses that the DSSS
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`sequence should be designed to avoid a high Peak to Average (PAR) ratio and is not limited to
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`binary sequences.
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`’908 patent at 7:56–65.
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`14.
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`A person of skill in the art would understand in view of the shared specification
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`that a DSSS signal as used in the claims includes the embodiments of a DSSS sequence
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`modulated by information bits.
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`15.
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`The shared specification contemplates, under “DSSS Signal Design,” selection of
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`a sequence with good autocorrelation properties that lacks a high peak to average ratio (PAR).
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`The specification also contemplates the use of non-binary sequences.
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`’908 patent at 7:25–44.
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`’908 patent at 7:54–65.
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`16.
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`Accordingly, a person of skill in the art would understand that DSSS sequences
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`include sequences with good cross-correlation properties that avoid high Peak to Average (PAR)
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`ratios and are not limited to binary sequences.
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`3.
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`ZADOFF CHU SEQUENCES
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`17.
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`Zadoff-Chu sequences are DSSS sequences as described in the shared
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`specification of the ’908 and ’302 patents.
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`18.
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`Zadoff-Chu sequences are designed to have good autocorrelation and cross-
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`correlation properties.
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`19.
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`For example, LTE uses Zadoff-Chu sequences to generate random access
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`preambles with zero correlation zone.
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`3GPP TS 36.211 V8.9.0 at 39.
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`20.
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`Numerous sources in the field also support the good autocorrelation and cross-
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`correlation properties of Zadoff-Chu sequences. For example, one paper observes that the
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`autocorrelation of a Zadoff-Chu sequence is optimal, in that it is zero for all nonzero shifts of the
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`sequence.
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`NEO-AUTO_0140454–NEO-AUTO_0140455 (Jeffrey Andrews, “A Primer on Zadoff Chu
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`Sequences”, arXiv, June 2023); see also NEO-AUTO_0140453–NEO-AUTO_0140460.
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`21.
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`As another example, a separate authoritative textbook explains that Zadoff Chu
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`codes were identified originally for their ideal periodic autocorrelation function and contain such
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`properties.
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`NEO-AUTO_0142690 (highlighting added).
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`NEO-AUTO_0142697 (highlighting added).
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`10
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`NEO-AUTO_0142698 (highlighting added).
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`11
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`NEO-AUTO_0142699 (highlighting added).
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`NEO-AUTO_0142707–708 (highlighting added) (Levanon and Mozeson, Radar Signals (Wiley
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`2004); see also NEO-AUTO_0142560–NEO–AUTO_0142986.
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`22.
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`Similar publications from IEEE explain the ideal autocorrelation properties of
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`Zadoff Chu Sequences.
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`14
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`NEO-AUTO_0140362–NEO-AUTO_0140365 (Li and Huang, “A Constructive Representation
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`for the Fourier Dual of the Zadoff-Chu Sequences”, IEEE Transactions on Information Theory,
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`Vol 53, No. 11, Nov. 2007, pp. 4221–4224) (highlighting added).
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`NEO-AUTO_0140359 (Popovic, “Spreading Sequences for Multi-Carrier CDMA Systems”,
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`(IEEE 1997)) (highlighting added).
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`NEO-AUTO_0140399 (David C. Chu, “Polyphase Codes with Good Periodic Correlation
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`Properties” (IEEE 1972)) (highlighting added).
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`NEO-AUTO_0140366 (Jamil and Linde, “A Comparison of Unfiltered and Filtered Complex
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`Spreading Sequences Based on Aperiodic Correlation Properties”, (IEEE 1998) (highlighting
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`added).
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`NEO-AUTO_0140546 (Baig and Jeoti, “A New ZCT Precoding Based SLM Technique for
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`PAPR Reduction in OFDM Systems,” (IEEE 2010)) (highlighted added).
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`23.
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`Similarly, Zadoff-Chu sequences do not have a high peak to average power ratio.
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`For example, publications in the industry show that Zadoff Chu Sequences have a peak to
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`average power ratio of 1 (0dB) and that the use of Zadoff Chu sequences reduces the peak to
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`average power ratio.
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`NEO-AUTO_0140454 (Jeffrey Andrews, “A Primer on Zadoff Chu Sequences”, arXiv, June
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`2023).
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`Lotter and Linde, “A Class of Bandlimited Complex Spreading Sequences with Analytic
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`Properties”, Proceedings of ISSSTA ’95 International Symposium on Spread Spectrum
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`Techniques and Applications (IEEE 1996).
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`NEO-AUTO_0140547–548 (Baig and Jeoti, “A New ZCT Precoding Based SLM Technique for
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`PAPR Reduction in OFDM Systems,” (IEEE 2010)) (highlighted added).
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`NEO-AUTO_0140356–NEO-AUTO_0140361 (Popovic, “Spreading Sequences for Multi-
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`Carrier CDMA Systems”, IEEE, 1997).
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`4.
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`RANDOM ACCESS PREAMBLE
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`24.
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`The Random Access Preamble transmitted on the PRACH in LTE networks is
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`generated from Zadoff-Chu Sequences, which, as described in the Zadoff Chu Sequences (3)
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`section above, are DSSS sequences.
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`
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`3GPP TS 36.211 v.8.9.0 at 39.
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`25.
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`And the random access preamble is used as a random access signal. See Appx. A:
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`LTE Standards, Section II.B.1 (“Random Access Preamble”).
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`26.
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`As discussed in Section 1 above (DSSS Signal In The Asserted Patents’
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`Specifications), the transmission of an unmodulated DSSS sequence is a DSSS signal.
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`Accordingly, the random access preamble is a DSSS Signal used as a random access signal.
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`27.
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`To the extent any modulation is required, there is no material difference in
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`implementing a DSSS signal formed from a DSSS sequence and a DSSS signal formed from a
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`DSSS sequence modulated with information bits of one. Accordingly, the implementation of a
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`signal generated from an unmodulated Zadoff-Chu sequence is the same as the implementation
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`of a Zadoff-Chu sequence modulated with information bits that are always one.
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`28.
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`To the extent that the random access preamble is not a direct sequence spread
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`spectrum signal used as a random access signal, there are no substantial differences between a
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`random access preamble and a direct sequence spread spectrum signal used as a random access
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`signal. The random access preamble performs substantially the same function; the random
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`access preamble is used to facilitate random access to a network. See Appx. A: LTE Standards,
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`Section II.B.1 (“Random Access Preamble”). The random access preamble also performs this
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`function in substantially the same way; the random access preamble provides a sequence
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`associated with the base station. See id. And the random access preamble is used to achieve
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`substantially the same result; the random access preamble is used to establish an ID for the
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`mobile station or mobile device and to establish uplink synchronization. See id.
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`5.
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`SOUNDING REFERENCE SIGNAL
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`29.
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`The SRS in LTE systems are generated from Zadoff Chu sequences. See
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`Appx. A: LTE Standards, Section II.E (“Sounding Reference Signal”).
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`30. Moreover, the SRS is used to probe the channel profile for channel quality
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`estimation consistent with probing signals and embodiments in the ’302 patent. See id; see also
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`supra Section 1 (“DSSS Signal In The Asserted Patents’ Specification”).
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`31.
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`Thus, the use of an SRS sequence is a DSSS signal used as a probing signal. This
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`is true even if the SRS is generated from an unmodulated Zadoff-Chu sequence for the same
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`reasons as described above in Section 1 (DSSS Signal In The Asserted Patents’ Specification).
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`32.
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`To the extent any modulation is required, there is no difference in implementing a
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`probing signal formed from a DSSS sequence and a probing signal formed from a DSSS
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`sequence modulated with information bits of one. Accordingly, the implementation of a signal
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`generated from an unmodulated Zadoff-Chu sequence is the same as the implementation of a
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`Zadoff-Chu sequence modulated with information bits that are always one.
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`33.
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`To the extent that an SRS is not a direct sequence spread spectrum signal used as
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`a probing signal, there are no substantial differences between an SRS and a DSSS signal used as
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`a probing signal. The SRS performs substantially the same function; the SRS is used to probe
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`the channel profile for channel quality estimation to enable frequency-selective scheduling on the
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`uplink. See Appx. A: LTE Standards, Section II.E (“Sounding Reference Signal”). The SRS
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`also performs this function in substantially the same way; the SRS is formed from a sequence
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`with properties contemplated for DSSS sequences as described in the ’302 specification, such as
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`having good autocorrelation properties and lacking a high peak to average ratio. See supra
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`Section 2 (“DSSS Sequence In The Asserted Patents’ Specification”). And the SRS is used to
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`achieve substantially the same result; obtaining channel information to be used for channel
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`quality estimation. See Appx. A: LTE Standards, Section II.E (“Sounding Reference Signal”).
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