TDMA communications apparatus

• US 20060114862A1
• Filed: 11/28/2005
• Published: 06/01/2006
• Est. Priority Date: 11/26/2004
• Status: Active Grant

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: Furuno Electric Co, Ltd
• Inventors: Hiraoka, Yasushi
• Granted Patent: US 7,620,022 B2
• Time in Patent Office: Days
• US Class Current: 370/337
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02

Abstract

A CPU of a TDMA communications apparatus examines whether a slot to be allocated for a next transmission is a first slot (S1). If the slot to be allocated is the first slot, the CPU examines whether there are any slots already allocated by other stations within a Selection Interval SI in a frame in which the next transmission of own station is to be allocated referring to a slot map in a memory and finds out a free slot within Selection Interval SI (S11). Then, the CPU allocates the free slot as a next transmit slot of the own station and sets the slot number of the free slot as the slot number of the next transmit slot (S12). Then, the CPU examines whether a slot adjacent to the next transmit slot of the own station is allocated to any of the other stations (S13). If either of the slots adjacent to the next transmit slot of the own station is already allocated to another station, the CPU examines a time-out value set by that station for the adjacent slot (S15) and sets an initial time-out value differing from the time-out value set by the other station for the adjacent slot (S16).

Claims

1. A TDMA communications apparatus for carrying out communication using TDMA technology in which a frame is divided into a plurality of slots in accordance with a prescribed time division scheme, each station transmits in the same slot allocated in as many successive frames as specified by a time-out value which is decremented by 1 from one frame to the next, and each station reserves a new slot for future transmissions together with an initial time-out value at a point in time when a previously set time-out value reaches a specific value, said TDMA communications apparatus comprising time-out value setting means for detecting a time-out value set by any other station for either of slots adjacent to the slot of own station to be allocated and for setting the initial time-out value at a value differing from the detected time-out value of the other station for the slot of the own station to be allocated at a point in time when the own station reserves the new slot.

2. The TDMA communications apparatus according to claim 1 further comprising transmission stop means for canceling transmission in the newly reserved slot if said transmission stop means detects that the time-out value set by the other station for a slot adjacent to the slot of own station to be allocated has reached said specific value in a slot in which the time-out value of the own station has also reached said specific value and further detects in a succeeding slot that the slot newly reserved by the own station for future transmissions coincides with a slot newly reserved by the other station of which time-out value has reached said same specific value.

3. The TDMA communications apparatus according to claim 1 or 2, wherein said time-out value setting means resets the time-out value of the own station to said specific value if said time-out value setting means detects that the time-out value set for the slot newly reserved by the own station coincides with the time-out value set by the other station for a newly reserved slot thereof adjacent to the slot of the own station to be allocated.