DM RS Based LTE Downlink Physical Layer

• US 20140192786A1
• Filed: 07/06/2011
• Published: 07/10/2014
• Est. Priority Date: 07/06/2011
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Skov, Peter, Wang, Xiaoyi, Miao, De Shan
• Granted Patent: US 9,848,415 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

It is provided an apparatus, including synchronizing means adapted to synchronize with a cell of a cellular communication system based on a synchronization signal and to obtain a cell identification of the cell; receiving means adapted to receive a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel; first obtaining means adapted to obtain a common demodulation reference symbol based on the cell identification and the received symbol; demodulating means adapted to demodulate a signal received on the physical broadcast channel based on the common demodulation reference symbol; user equipment means adapted to provide a user equipment functionality of the communication system.

Claims

1-31. -31. (canceled)

32. Apparatus, comprising

synchronizing means adapted to synchronize with a cell of a cellular communication system based on a synchronization signal and to obtain a cell identification of the cell;

receiving means adapted to receive a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel;

first obtaining means adapted to obtain a common demodulation reference symbol based on the cell identification and the received symbol;

demodulating means adapted to demodulate a signal received on the physical broadcast channel based on the common demodulation reference symbol;

user equipment means adapted to provide a user equipment functionality of the communication system.

33. Apparatus according to claim 32, wherein the demodulating means is

further adapted to demodulate a signal received on a physical downlink control channel based on the common demodulation reference symbol;

or

further adapted to demodulate a signal received on a physical downlink control channel based on a specific demodulation reference symbol, wherein the apparatus comprises second obtaining means adapted to obtain a specific demodulation reference symbol based on a specific identification received from the cell, wherein

34. Apparatus according to claim 33, wherein

the demodulating means is adapted to demodulate a signal received on a physical downlink shared channel allocated in a subframe together with the physical downlink control channel based on the specific demodulation reference symbol.

35. Apparatus according to claim 32, further comprising

RACH response detecting means adapted to detect a random access channel response signal received on a physical downlink shared channel;

the demodulating means is further adapted to demodulate the physical downlink shared channel and a physical downlink control channel based on the common demodulation reference symbol to obtain a demodulated RACH response signal.

36. Apparatus according to claim 32, further comprising

preamble providing means adapted to provide a preamble including a PRACH resource index;

RACH response detecting means adapted to detect a random access channel response signal received on a physical downlink shared channel;

third obtaining means adapted to obtain a specific RACH demodulation reference symbol based on the PRACH resource index;

wherein

the demodulating means is further adapted to demodulate the physical downlink shared channel and a physical downlink control channel based on the specific RACH demodulation reference symbol.

37. Apparatus, comprising

base station means adapted to provide a base station functionality in a cell of a cellular communication system;

broadcasting means adapted to broadcast a common demodulation reference signal to all user equipments in the cell, wherein the common demodulation reference signal is based on a cell identification of the cell, and the common demodulation reference symbol is transmitted only on one or more subcarriers and in subframes which carry at least one symbol of a physical broadcast channel.

38. Apparatus according to claim 37, further comprising

specific demodulation reference symbol providing means adapted to provide a specific demodulation reference symbol based on an identification specification specific for one of the user equipments, and

physical downlink control channel modulating means adapted to modulate a symbol of a physical downlink control channel to the one of the user equipments based on the specific demodulation reference symbol.

39. Apparatus according to claim 37, further comprising

RACH response providing means adapted to provide a RACH response message in response to a received preamble, wherein the RACH response message is provided in a physical downlink shared channel allocated with a physical downlink control channel and modulated based on the common demodulation reference symbol.

40. Apparatus according to claim 37, further comprising

obtaining means adapted to obtain a RACH demodulation reference symbol based on a PRACH resource index comprised in a preamble received from one of the user equipments;

RACH response providing means adapted to provide a RACH response message in response to the preamble; and

modulating means adapted to modulate the physical downlink shared channel to the one of the user equipments based on the RACH demodulation reference symbol, wherein the physical downlink shared channel comprises the RACH response message.

41. Method, comprising

synchronizing with a cell of a cellular communication system based on a synchronization signal to obtain a cell identification of the cell;

receiving a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel;

obtaining a common demodulation reference symbol based on the cell identification and the received symbol;

demodulating a signal received on the physical broadcast channel based on the common demodulation reference symbol;

providing a user equipment functionality of the communication system.

42. Method according to claim 41, further comprising

demodulating a signal received on a physical downlink control channel based on the common demodulation reference symbol;

or

demodulating a signal received on a physical downlink control channel based on a specific demodulation reference symbol, wherein the method further comprises obtaining a specific demodulation reference symbol based on a specific identification received from the cell.

43. Method according to claim 42, further comprising

demodulating a signal received on a physical downlink shared channel allocated in a subframe together with the physical downlink control channel based on the specific demodulation reference symbol.

44. Method according to claim 41, further comprising

detecting a random access channel response signal received on a physical downlink shared channel;

and

demodulating the physical downlink shared channel and a physical downlink control channel based on the common demodulation reference symbol to obtain a demodulated RACH response signal.

49. A computer program product including a program comprising software code portions being arranged, when run on a processor of an apparatus, to perform the method according to claim 41.

45. Method, comprising

providing a base station functionality in a cell of a cellular communication system;

broadcasting a common demodulation reference signal to all user equipments in the cell, wherein the common demodulation reference signal is based on a cell identification of the cell, and the common demodulation reference symbol is transmitted only on one or more subcarriers and in subframes which carry at least one symbol of a physical broadcast channel.

46. Method according to claim 45, further comprising

providing a specific demodulation reference symbol based on an identification specification specific for one of the user equipments, and

modulating a symbol of a physical downlink control channel to the one of the user equipments based on the specific demodulation reference symbol.

47. Method according to claim 46, further comprising

modulating a physical downlink shared channel to the one of the user equipments based on the specific demodulation reference symbol, wherein the physical downlink shared channel is allocated in a subframe together with the physical downlink control channel to the one of the user equipments.

48. Method according to claim 45, further comprising

obtaining a RACH demodulation reference symbol based on a PRACH resource index comprised in a preamble received from one of the user equipments;

providing a RACH response message in response to the preamble; and

modulating the physical downlink shared channel to the one of the user equipments based on the RACH demodulation reference symbol, wherein the physical downlink shared channel comprises the RACH response message.