APPARATUS AND METHOD FOR ENHANCING FEATURES OF UPLINK REFERENCE SIGNALS

• US 20110164489A1
• Filed: 01/07/2011
• Published: 07/07/2011
• Est. Priority Date: 01/07/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: PAPASAKELLARIOU, Aris, Cho, Joon-Young
• Granted Patent: US 8,873,362 B2
• Time in Patent Office: Days
• US Class Current: 370/203
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Methods and apparatuses for configuring and transmitting Reference Signals (RS) accompanying data signals from User Equipments (UEs), such that Sounding Reference Signals (SRS) are transmitted from some UEs over a part of a possible transmission bandwidth, with or without the use of SRS bandwidth hopping.

Claims

1. A method for assigning a first Cyclic Shift (CS) and a first Orthogonal Cover Code (OCC) to a first User Equipments (UE) for a first Reference Signal (RS) transmission and a second CS and a second OCC to a second UE for a second RS transmission, in a communication system wherein a Base Station (BS) transmits in Physical Downlink Control Channels (PDCCHs) a respective set of Downlink Control Information (DCI) formats to a plurality of UEs, wherein each DCI format from a subset of the set of DCI formats includes Information Elements (IEs) configuring data and RS transmissions from the plurality of UEs to the BS, and wherein the IEs includes binary elements and an RS Configuration (RSC) IE assigning a CS and an OCC for an RS transmission by a UE, the method comprising the steps of:

indicating, by the BS, through an RSC IE included in a first DCI format from a subset of the set of DCI formats, the first CS and the first OCC for the first RS transmission by the first UE; and

indicating, by the BS, through an RSC IE in a second DCI format from a subset of the set of DCI formats, the second CS and the second OCC for the second RS transmission by the second UE,

wherein the first CS is different than the second CS, and the first OCC is different than the second OCC.

2. The method of claim 1, wherein a first set of CSs is associated with the first OCC and a second set of CS is associated with the second OCC, and

wherein the first set of CSs and the second set of CSs do not have any common elements.

3. The method of claim 2, wherein all elements in the first set of CSs or in the second set of CSs are separated by a same value.

4. The method of claim 1, wherein the first UE belongs to a first class of UEs and is assigned the first OCC for its RS transmission, and the second UE belongs to a second class of UEs and is assigned either the first or the second OCC for its RS transmission.

5. The method of claim 4, wherein the set of CSs associated with the first OCC for the first class of UEs does not have any common elements with the set of CSs associated with the first OCC for the second class of UEs.

6. A method for restricting a Reference Signal (RS) bandwidth size and an RS bandwidth location, in a communication system wherein a User Equipment (UE) transmits an RS to a Base Station (BS), the RS bandwidth size being less than or equal to a predefined maximum RS bandwidth size, the method comprising the steps of:

transmitting, by the UE, an RS with a first bandwidth size and in a first bandwidth location in a first set of sub-frames; and

transmitting, by the UE, an RS with a second bandwidth size and in a second bandwidth location in a second set of sub-frames,

wherein the second bandwidth size is smaller than the predefined maximum RS bandwidth size.

7. The method of claim 6, wherein the first bandwidth size is equal to the second bandwidth size.

8. The method of claim 6, wherein the second set of sub-frames is informed to the UE, by the BS, using a bit-map.

9. The method of claim 8, wherein the first set of sub-frames is equal to the second set of sub-frames.

11. The method of claim 9, wherein the predetermined bandwidth location for the initial RS transmission and the set of bandwidth locations are informed to the UE by the BS.

10. A method for a User Equipment (UE) to determine a bandwidth location for a Reference Signal (RS) transmission from a set of bandwidth locations, in a communication system wherein the UE transmits an RS to a Base Station (BS), the method comprising the steps of:

determining, by the UE, a number of RS bandwidth locations according to a bandwidth location hopping pattern, starting from a predetermined bandwidth location for an initial RS transmission or from a next bandwidth location, determined according to a hopping pattern relative to a bandwidth location of a last RS transmission, until a bandwidth location that belongs in the set of bandwidth locations is identified; and

transmitting, by the UE, an RS in an identified bandwidth location.

12. A method for a first User Equipment (UE) to transmit a first User Equipments (UEs) over a first bandwidth and for a second UE to transmit a second RS over a second bandwidth, in a communication system, wherein a plurality of UEs transmit RSs to a Base Station (BS), the method comprising the steps of:

transmitting, by the first UE, the first RS according to a first bandwidth hopping pattern spanning the first bandwidth; and

transmitting, by the second UE, the second RS according to a second bandwidth hopping pattern spanning the second bandwidth,

wherein the first bandwidth is larger than the second bandwidth and includes at least a portion of the second bandwidth.

13. The method of claim 12, wherein a number of second RS transmissions with the second bandwidth hopping pattern before the second RS is transmitted again at a same bandwidth location is smaller than a number of first RS transmissions with the first bandwidth hopping pattern before the first RS is transmitted again at a same bandwidth location.

14. The method of claim 12, wherein the BS informs the second UE to use the second bandwidth hopping pattern.

15. A method for a User Equipment (UE) to transmit Reference Signals (RSs) during a same transmission symbol of a Transmission Time Interval (TTI), in a communication system wherein the UE communicates with a Base Station (BS), the method comprising the steps of:

informing, by the BS, the UE of multiple non-contiguous bandwidth locations for simultaneous RS transmission; and

transmitting, by the UE, multiple RSs at the multiple non-contiguous bandwidth locations,

wherein at least some of the multiple RSs have a bandwidth size that is different than a bandwidth size of other signals that the UE may transmit in a same TTI.

16. The method of claim 15, wherein the BS informs the UE of the multiple non-contiguous bandwidth locations, in a set of bandwidth locations, using a bit-map.

17. The method of claim 15, wherein at different TTIs a subset of the RSs are transmitted in same bandwidths and remaining RSs are transmitted in different bandwidths according to a bandwidth hopping pattern.

18. A User Equipment (UE) apparatus for transmitting a Reference Signal (RS) having a bandwidth size that is equal to or smaller than a predefined maximum RS bandwidth size, the UE apparatus comprising:

a transmitter for transmitting an RS with a first bandwidth size and in a first bandwidth location in a first set of sub-frames, and transmitting an RS with a second bandwidth size and in a second bandwidth location during a second set of sub-frames, wherein the second bandwidth size is smaller than the predefined maximum RS bandwidth size.

19. The UE apparatus of claim 18, wherein the second set of sub-frames is informed to the UE using a bit-map.

20. A User Equipment (UE) apparatus for transmitting a Reference Signal (RS) at a bandwidth location from a set of bandwidth locations, the UE apparatus comprising:

a bandwidth location evaluation unit for determining a number of RS bandwidth locations according to a bandwidth location hopping pattern, starting from a predetermined bandwidth location for an initial RS transmission or from a next bandwidth location determined according to a hopping pattern relative to a bandwidth location of a last RS transmission, until a bandwidth location that belongs in the set of bandwidth locations is identified; and

a transmitter for transmitting the RS in an identified bandwidth location.

21. The UE apparatus of claim 20, wherein the predetermined bandwidth location for the initial RS transmission and the set of bandwidth locations are informed to the UE by a base station.

22. A User Equipment (UE) apparatus for transmitting a Reference Signal (RS) over a first bandwidth or over a second bandwidth, the UE apparatus comprising:

a transmitter for transmitting an RS according to a first bandwidth hopping pattern spanning the first bandwidth, and for transmitting an RS according to a second bandwidth hopping pattern spanning a second bandwidth,

wherein the first bandwidth is larger than the second bandwidth and includes at least a portion of the second bandwidth.

23. The UE apparatus of claim 22, wherein a number of RS transmissions with the second bandwidth hopping pattern, before an RS is transmitted again at a same bandwidth location, is smaller than a number of RS transmissions with the first bandwidth hopping pattern before an RS is transmitted again at a same bandwidth location.

24. A User Equipment (UE) apparatus for transmitting Reference Signals (RSs) during a same transmission symbol of a Transmission Time Interval (TTI), wherein each of the RSs has a bandwidth size that is different than a bandwidth size of other signals that the UE apparatus may transmit in the same TTI, the UE apparatus comprising:

a transmitter for transmitting an RS in a first mode over a contiguous bandwidth, and transmitting an RS in a second mode at multiple non-contiguous bandwidth locations.

25. The UE apparatus of claim 24, wherein at different TTIs, a subset of the RSs is transmitted in a same bandwidth and remaining RSs are transmitted in different bandwidths according to a bandwidth hopping pattern.