US 7154961

Analysis of U.S. Patent No. 7,154,961

Date of Analysis: April 28, 2026

This report provides a summary of United States Patent No. 7,154,961, including its bibliographic details and a plain-language explanation of its independent claims. Information is based on the patent's official text.

Bibliographic Information

• Title: Constellation rearrangement for ARQ transmit diversity schemes
• Assignee: The current assignee of record is SWIRLATE IP LLC. The original assignee was Matsushita Electric Industrial Co., Ltd.
• Inventors: Christian Wengerter, Alexander Golitschek Edler Von Elbwart, Eiko Seidel
• Filing Date: October 18, 2002
• Issue Date: December 26, 2006
• Abstract: An ARQ (re-) transmission method of transmitting data in a wireless communication system wherein data packets are transmitted from a transmitter to a receiver, using a first transmission and a second transmission based on a repeat request. The method comprises the steps of modulating data at the transmitter using a first signal constellation pattern to obtain a first data symbol. The first data symbol is transmitted as the first transmission to the receiver using a first diversity branch. Further, the data is modulated at the transmitter using a second signal constellation pattern to obtain a second data symbol. Then, the second data symbol is transmitted as the second transmission to the receive over a second diversity branch. Finally, the received first and second data symbol data symbol are diversity combined at the receiver. The invention further relates to a transmitter and a receiver embodied to carry out the method of the invention.

Litigation Status

As of today's date, this patent has been the subject of numerous litigation proceedings. It has been asserted in various U.S. District Courts, including cases in Texas, Delaware, and Washington, by the current assignee, SWIRLATE IP LLC. No active cases for 2026 in the Court of Appeals for the Federal Circuit (CAFC) were immediately identified in the preliminary search.

Plain-Language Summary of Independent Claims

This patent contains two independent claims: Claim 1 (and its various dependent claims which add specificity) and Claim 11.

Independent Claim 1 (and related claims 2-10): A Method for Reliable Data Retransmission

Independent claim 1 describes a method for re-transmitting data in a wireless system when the first attempt fails (a process known as Automatic Repeat reQuest or ARQ). The core idea is to improve the reliability of the retransmission by using different modulation schemes for the original transmission and the subsequent retransmission, which are sent over different "diversity branches" (e.g., different antennas or frequencies).

In simple terms, the process is as follows:

1. A data packet is modulated using a first "modulation scheme" (like 16-QAM) to create data symbols.
2. These symbols are sent to a receiver over a first communication path (a "diversity branch").
3. If the receiver requests a retransmission, the same data packet is modulated again, but this time using a second, different modulation scheme.
4. These new symbols are sent over a second communication path.
5. The receiver, knowing which modulation scheme was used for each transmission, demodulates both sets of symbols.
6. Finally, it combines the information from both transmissions to reconstruct the original data with a higher chance of success.

Dependent claims add further specifics:

• Claim 1 itself specifies that the modulation is 16-QAM and that a specific number of different modulation schemes are used.
• Claim 2 focuses on the outcome: the different modulation schemes are chosen specifically to reduce differences in the "reliability" of the bits after they are combined, effectively averaging out potential errors.
• Claims 3 & 4 specify whether the same data (a "single redundancy version") or slightly different data ("multiple redundancy versions") is sent in the transmissions.
• Claim 5 explains how to create the different modulation schemes: either by "interleaving" (shuffling the order of the bits within a symbol) or "inverting" (flipping the bit values).
• Claims 7-10 detail more complex scenarios involving more than two diversity branches and transmissions, and prioritizing certain types of data bits ("systematic bits") to have higher reliability.

Independent Claim 11: A Transmitter for Implementing the Method

This claim describes the physical transmitter device built to perform the method outlined above. The transmitter must include:

1. An interleaver or inverter: A component that can change the bit patterns to create the different modulation schemes.
2. A mapping unit (modulator): This part takes the data packets and, using the different modulation schemes, converts them into the data symbols for transmission.
3. A transmission unit: This component sends the first set of symbols over a first diversity branch and the second set of symbols over a second diversity branch.