Method For Transmitting And Receiving Random Access Request And Transmitting And Receiving Random Access Response
Patent No. US12267876 (titled "Method For Transmitting And Receiving Random Access Request And Transmitting And Receiving Random Access Response") was filed by Pantech Corp on Sep 22, 2023.
What is this patent about?
’876 is related to the field of wideband radio access systems, specifically addressing the problem of user equipment (UE) correctly identifying random access responses (RAR) from a base station (BS) following a random access request (RACH). In cellular communication, multiple UEs may attempt access simultaneously using the same random access sequence. This can lead to a UE misinterpreting another UE's RAR as its own, causing synchronization errors and resource contention.
The underlying idea behind ’876 is to embed time-related information about the RACH transmission within the RAR. This allows the UE to verify if the received RAR corresponds to its specific RACH attempt. By including the subframe number in which the RACH was transmitted, the UE can compare this value with the subframe number of its own transmission. A match confirms that the RAR is indeed intended for that UE.
The claims of ’876 focus on a method and apparatus for a UE to perform a random access procedure. The UE transmits a random access preamble in a first subframe, determines a time period for receiving a random access response, receives the random access response within that time period, and then determines if the received response is actually a response to the transmitted preamble. This determination is based on information generated using the subframe number of the first subframe, with a fixed offset of three subframes after the end of the preamble transmission defining the start of the reception window.
In practice, the UE transmits a RACH and then calculates a specific time window to expect the corresponding RAR. This window is determined by adding a fixed offset of three subframes to the end of the RACH transmission. The UE then listens for a RAR within this window. If a RAR is received, the UE checks if the subframe number used to calculate the window matches the subframe number of its original RACH transmission. This verification step ensures that the UE only acts upon RARs intended for it.
This approach differs from prior solutions by explicitly incorporating timing information to disambiguate RARs. Instead of relying solely on the random access sequence, which can be the same for multiple UEs, the inclusion of the subframe number provides a unique identifier for each RACH attempt. The fixed offset of three subframes defines a reception window , simplifying the UE's search for its RAR and reducing the likelihood of misinterpreting other UEs' responses. This method avoids the signaling overhead of including the subframe number in the RAR itself, as the UE can derive the expected subframe number independently.
How does this patent fit in bigger picture?
Technical landscape at the time
In the late 2000s when ’876 was filed, wireless communication systems commonly relied on specific time slots and random access channels for user equipment to initiate communication with a base station. At a time when contention-based access was typically implemented using slotted ALOHA schemes, managing collisions and ensuring accurate timing were non-trivial, especially in wideband systems. When hardware or software constraints made precise synchronization challenging, user equipment could erroneously interpret responses intended for other devices as their own.
Novelty and Inventive Step
The examiner allowed the claims because the prior art, specifically Fisher et al. and Jen et al., either individually or combined, do not teach or make obvious a method including the specific limitations of claim 19. These limitations include determining the random access response based on information generated using the subframe number of the first subframe, and starting the time period after the end time of transmitting the random access preamble, where the starting time is obtained by adding an offset of three to a subframe number corresponding to the end time of transmitting the random access preamble. Independent claim 22 was also deemed allowable for similar reasons.
Claims
US12,267,876 has 6 claims, of which claims 1 and 4 are independent. The independent claims focus on a method and user equipment (UE) for performing a random access procedure, including transmitting a random access preamble and receiving a random access response. The dependent claims generally elaborate on the selection of the random access preamble and the association of the random access response with information generated using the subframe number.
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Date
Description
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US12267876
- Application Number
- US18371735
- Filing Date
- Sep 22, 2023
- Status
- Granted
- Expiry Date
- Dec 31, 2028
- External Links
- Slate, USPTO, Google Patents